Continuous catalytic production of 1,3-dihydroxyacetone: Sustainable approach combining perfusion cultures and immobilized cells.

Currently, the predominant method for the industrial production of 1,3-dihydroxyacetone (DHA) from glycerol involves fed-batch fermentation. However, previous research has revealed that in the biocatalytic synthesis of DHA from glycerol, when the DHA concentration exceeded 50 g·L-1, it significantly inhibited microbial growth and metabolism, posing a challenge in maintaining prolonged and efficient catalytic production of DHA. In this study, a new integrated continuous production and synchronous separation (ICSS) system was constructed using hollow fiber columns and perfusion culture technology. Additionally, a cell reactivation technique was implemented to extend the biocatalytic ability of cells. Compared with fed-batch fermentation, the ICSS system operated for 360 h, yielding a total DHA of 1237.8 ± 15.8 g. The glycerol conversion rate reached 97.7 %, with a productivity of 3.44 g·L-1·h-1, representing 485.0 % increase in DHA production. ICSS system exhibited strong operational characteristics and excellent performance, indicating significant potential for applications in industrial bioprocesses.

MemeNet: Toward a Reliable Local Projection for Image Recognition via Semantic Featurization.

When we recognize images with the help of Artificial Neural Networks (ANNs), we often wonder how they make decisions. A widely accepted solution is to point out local features as decisive evidence. A question then arises: Can local features in the latent space of an ANN explain the model output to some extent? In this work, we propose a modularized framework named MemeNet that can construct a reliable surrogate from a Convolutional Neural Network (CNN) without changing its perception. Inspired by the idea of time series classification, this framework recognizes images in two steps. First, local representations named memes are extracted from the activation map of a CNN model. Then an image is transformed into a series of understandable features. Experimental results show that MemeNet can achieve accuracy comparable to most models' through a set of reliable features and a simple classifier. Thus, it is a promising interface to use the internal dynamics of CNN, which represents a novel approach to constructing reliable models.

Prolonging valley polarization lifetime through gate-controlled exciton-to-trion conversion in monolayer molybdenum ditelluride.

Monolayer 2D semiconductors provide an attractive option for valleytronics due to valley-addressability. But the short valley-polarization lifetimes for excitons have hindered potential valleytronic applications. In this paper, we demonstrate a strategy for prolonging the valley-polarization lifetime by converting excitons to trions through efficient gate control and exploiting the much longer valley-polarization lifetimes for trions than for excitons. At charge neutrality, the valley lifetime of monolayer MoTe2 increases by a factor of 1000 to the order of nanoseconds from excitons to trions. The exciton-to-trion conversion changes the dominant depolarization mechanism from the fast electron-hole exchange for excitons to the slow spin-flip process for trions. Moreover, the degree of valley polarization increases to 38% for excitons and 33% for trions through electrical manipulation. Our results reveal the depolarization dynamics and the interplay of various depolarization channels for excitons and trions, providing an effective strategy for prolonging the valley polarization.

Interplay between liver circadian rhythm and regeneration after PHx.

Diurnal oscillations in gene expression are a hallmark of the liver internal clock and can be regulated by a variety of environmental stimuli. The circadian rhythm and liver regeneration (LR) are intimately linked. However, how they affect each other at the transcriptomic level is mainly unknown. Here, we revealed that partial hepatectomy (PHx)-induced LR led to reprogramming of rhythmic gene expression profiles as a consequence of disrupted BMAL1 occupation on the chromatin, while the rhythm of core clock genes remained robust. Furthermore, we demonstrated retarded LR when PHx was carried out in the evening, possibly due to the accumulation of DEC1. In summary, our data offer a broad perspective of the relationship between circadian rhythm and LR and suggest that the timing of PHx should be considered in the clinic application.

Founder cells for hepatocytes during liver regeneration: from identification to application.

Liver regeneration (LR) capacity in vertebrates developed through natural selection over a hundred million years of evolution. To maintain homeostasis or recover from various injuries, liver cells must regenerate; this process includes the renewal of parenchymal and nonparenchymal cells as well as the formation of liver structures. The cellular origin of newly grown tissue is one of the critical questions in this area and has been a subject of prolonged debate. The regenerative tissue may derive from either hepatocyte self-duplication or liver stem/progenitor cells (LSPCs). Recently, hepatocyte subpopulations and cholangiocytes were also described as important founder cells. The niche that triggers the proliferation of hepatocytes and the differentiation of LSPCs has been extensively studied. Meanwhile, in vitro culture systems for liver founder cells and organoids have been developed rapidly for mechanistic studies and potential therapeutic purposes. This review summarizes the cellular sources and niches that give rise to renewed hepatocytes during LR, and it also describes in vitro culture studies of those founder cells for future applications, as well as current reports for stem cell-based therapies for liver diseases.

GSK923295 as a potential antihepatocellular carcinoma agent causing delay on liver regeneration after partial hepatectomy.

BACKGROUND: The clinical trials emerged centromere protein E inhibitor GSK923295 as a promising anticancer drug, but its function in hepatocellular carcinoma (HCC) remain needs to be fully elucidated, especially as chemotherapy after hepatectomy for liver tumors. We aimed to describe anti-HCC activities of GSK923295 and compare its antiproliferative effects on liver regeneration after partial hepatectomy (PH). METHODS: All subjects were randomized to treatment with either vehicle or GSK923295. Antitumor activity of GSK923295 was assessed by xenograft growth assays. The C57BL/6 mice were subjected to 70% PH and the proliferation was calculated by liver coefficient, further confirmed by immunohistochemistry. The proliferation and cell cycle analysis of liver cell AML12 and HCC cells LM3, HUH7, and HepG2 were investigated using the cell counting kit-8 assay and Flow Cytometry. The chromosome misalignment and segregation in AML12 cells were visualized by immunofluorescence. RESULTS: Treatment with GSK923295 induced antiproliferation in HCC cell lines. It also caused delay on HCC tumor growth instead of regression both in a HCC cell line xenograft model and patient-derived tumor xenograft model. With microarray analysis, CENtromere Protein E was gradually increased in mouse liver after PH. Exposure of liver cells to GSK923295 resulted in delay on a cell cycle in mitosis with a phenotype of misaligned chromosomes and chromosomes clustered. In 70% PH mouse model, GSK923295 treatment also remarkably reduced liver regeneration in later stage, in parallel with the mitotic marker phospho-histone H3 elevation. CONCLUSION: The anticancer drug GSK923295 causes a significant delay on HCC tumor growth and liver regeneration after PH in later stage.

DUSP1 inhibits cell proliferation, metastasis and invasion and angiogenesis in gallbladder cancer.

DUSP1/MKP1 is a dual-specific phosphatase that regulates MAPK activity and is known to play a key role in tumor biology. Its function in gallbladder cancer (GBC) remains largely unknown, however. By exploring its activities in two GBC cell lines (SGC996 and GBC-SD), DUSP1 was found to inhibit GBC cell proliferation, migration and invasion. Moreover, DUSP1 inhibited GBC growth and metastasis in nude mice subcutaneously xenografted with SGC996 cells. The tumor suppression appeared to be mediated via the DUSP1-pERK/MAPK-MMP2 signal pathway. Angiogenesis was associated with the tumor metastasis in the mouse model and was impaired by DUSP1, which suppressed VEGF expression. These results suggest that DUSP1 suppresses GBC growth and metastasis by targeting the DUSP1-pERK-MMP2/VEGF axis. Identification of the DUSP1-pERK-MMP2/VEGF signals may provide new biomarkers and/or therapeutic targets to better suppress GBC metastasis in the future.

The evaluative value of Sema3C and MFN2 co-expression detected by immunohistochemistry for prognosis in hepatocellular carcinoma patients after hepatectomy.

BACKGROUND: The ability to evaluate the prognosis of hepatocellular carcinoma (HCC) following hepatectomy using biological markers is of great importance. MATERIALS AND METHODS: In this study, we collected samples from 54 patients with HCC after hepatectomy. Immunohistochemistry was used to detect the expression of Sema3C and MFN2 in the HCC samples. RESULTS: Immunohistochemistry results showed that Sema3C and MFN2 co-expression was significantly associated with tumor size. In addition, a significant association between high Sema3C and low MFN2 levels and shorter overall survival was noted, when Sema3C and MFN2 co-expression was analyzed. CONCLUSION: The results suggest that the correlative expression level of Sema3C and MFN2 has a strong value in the prognosis of patients with HCC following hepatectomy.

Circulating tumor DNA in hepatocellular carcinoma: trends and challenges.

Molecular characterization of individual patients' tumor cells is becoming increasingly important in offering effective treatment for patients in clinical practice. Recent advances in the field have indicated that circulating tumor DNA (ctDNA) has huge potential to serve as a biomarker for early detection and precision treatment as well as prognosis of hepatocellular carcinoma (HCC). As ctDNA in HCC patients harbors the molecular characteristics of HCC tumor cells, ctDNA analysis in the blood may be sufficient for convenient, non-invasive and accurate detection, providing information for HCC diagnosis, treatment and prognosis. In this review, we will summarize and discuss current trends and challenges of ctDNA application in HCC.

Autophagy in 5-Fluorouracil Therapy in Gastrointestinal Cancer: Trends and Challenges.

OBJECTIVE: 5-Fluorouracil (5-FU)-based combination therapies are standard treatments for gastrointestinal cancer, where the modulation of autophagy is becoming increasingly important in offering effective treatment for patients in clinical practice. This review focuses on the role of autophagy in 5-FU-induced tumor suppression and cancer therapy in the digestive system. DATA SOURCES: All articles published in English from 1996 to date those assess the synergistic effect of autophagy and 5-FU in gastrointestinal cancer therapy were identified through a systematic online search by use of PubMed. The search terms were "autophagy" and "5-FU" and ("colorectal cancer" or "hepatocellular carcinoma" or "pancreatic adenocarcinoma" or "esophageal cancer" or "gallbladder carcinoma" or "gastric cancer"). STUDY SELECTION: Critical reviews on relevant aspects and original articles reporting in vitro and/or in vivo results regarding the efficiency of autophagy and 5-FU in gastrointestinal cancer therapy were reviewed, analyzed, and summarized. The exclusion criteria for the articles were as follows: (1) new materials (e.g., nanomaterial)-induced autophagy; (2) clinical and experimental studies on diagnostic and/or prognostic biomarkers in digestive system cancers; and (3) immunogenic cell death for anticancer chemotherapy. RESULTS: Most cell and animal experiments showed inhibition of autophagy by either pharmacological approaches or via genetic silencing of autophagy regulatory gene, resulting in a promotion of 5-FU-induced cancer cells death. Meanwhile, autophagy also plays a pro-death role and may mediate cell death in certain cancer cells where apoptosis is defective or difficult to induce. The dual role of autophagy complicates the use of autophagy inhibitor or inducer in cancer chemotherapy and generates inconsistency to an extent in clinic trials. CONCLUSION: Autophagy might be a therapeutic target that sensitizes the 5-FU treatment in gastrointestinal cancer.

Adenoviral delivery of truncated MMP-8 fused with the hepatocyte growth factor mutant 1K1 ameliorates liver cirrhosis and promotes hepatocyte proliferation.

Liver cirrhosis is a chronic liver disease caused by chronic liver injury, which activates hepatic stellate cells (HSCs) and the secretion of extracellular matrix (ECM). Cirrhosis accounts for an extensive level of morbidity and mortality worldwide, largely due to lack of effective treatment options. In this study, we have constructed a fusion protein containing matrix metal-loproteinase 8 (MMP-8) and the human growth factor mutant 1K1 (designated cMMP8-1K1) and delivered it into hepatocytes and in vivo and in cell culture via intravenous injection of fusion protein-harboring adenovirus. In doing so, we found that the cMMP8-1K1 fusion protein promotes the proliferation of hepatocytes, likely resulting from the combined inhibition of type I collagen secretion and the degradation of the ECM in the HSCs. This fusion protein was also observed to ameliorate liver cirrhosis in our mouse model. These changes appear to be linked to changes in downstream gene expression. Taken together, these results suggest a possible strategy for the treatment of liver cirrhosis and additional work is warranted.

Effect of fibulin-5 on adhesion, migration and invasion of hepatocellular carcinoma cells via an integrin-dependent mechanism.

AIM: To elucidate the role of fibulin-5 (FBLN-5) as a suppressor of hepatocellular carcinoma (HCC) cell metastasis via integrin. METHODS: The expression of FBLN-5 was determined by immunohistochemistry in 140 HCC samples and matched normal tissues, and was further confirmed by RT-PCR and Western blot analyses in various cell lines. Recombinant FBLN-5 was expressed in Escherichia coli BL21(DE3), purified and used in cell attachment assays. Expression of a specific plasmid or a specific siRNA in HCC cells resulted in the overexpression or knockdown of FBLN-5, respectively. Further, the migration and invasion of HCC cells were investigated using the Boyden chamber and transwell assays. The concentration of secreted matrix metalloproteinase 7 (MMP-7) was determined using ELISA. RESULTS: FBLN-5 expression was found to be downregulated in HCC. Its expression was significantly correlated with advanced tumor metastasis; this was indicative of poor 5-year overall survival. Recombinant full-length human FBLN-5 promoted the attachment of HCC cells via integrins: it inhibited HCC cell adhesion and migration to fibronectin in a concentration-dependent manner. It also inhibited HCC cell migration and invasion through an integrin-binding arginine-glycine-aspartic acid (RGD) motif by downregulating MMP-7. CONCLUSION: These results suggest that lower FBLN-5 expression is an important indicator of poor survival and that FBLN-5 inhibits HCC motility via an integrin-dependent mechanism. RGD-dependent suppression of MMP-7 by FBLN-5 might contribute to the development of new therapeutic strategies for HCC.

Decorin accelerates the liver regeneration after partial hepatectomy in fibrotic mice.

BACKGROUND: Considering the existence of a large number of liver cell degeneration and necrosis in fibrotic liver, liver function was damaged severely and could not effectively regenerate after partial hepatectomy (PHx). The aim of this study was to investigate whether decorin (DCN) could promote the liver regeneration after PHx in fibrotic mice. METHODS: Forty mice (5-week-old, Balb/c) were injected with CCl4 intraperitoneally and liver fibrosis model was established after 5 weeks. The survival mice were randomly divided into two groups: control group and DCN group. Then, we performed 70% PHx on all these mice and injected DCN or phosphate-buffered saline plus normal saline (NS) to each group, respectively, after surgery. Liver body weight ratio (LBR), quantitative real-time polymerase chain reaction, and immunohistochemistry were used to analyze liver regeneration and fibrosis degree in both groups, and to find out whether exogenous protein DCN could promote the regeneration of fibrosis liver after PHx. RESULTS: Expressions of a-smooth muscle actin (SMA) mRNA and LBR had significant increases in the DCN group at postoperative Day 3 (POD 3, P < 0.05). The protein expressions of CD31, a-SMA, and tumor necrosis factor (TNF)-a were higher in the DCN group than those in the control group by immunohistochemistry at POD 3 (P < 0.05). CONCLUSION: Exogenous protein DCN could promote liver regeneration after PHx in fibrotic mice.

[Effects of autophagy on 5-fluorouracil cytotoxicity for gallbladder carcinoma GBC-SD cell].

OBJECTIVE: To explore the effects of autophagy on 5-fluorouracil (5-FU) cytotoxicity for gallbladder carcinoma GBC-SD cell and discuss a novel and promising strategy of autophagy inhibitor for increasing the clinical efficacy of 5-FU in the treatment of gallbladder carcinoma. METHODS: After a pre-treatment of autophagy inhibitors, such as chloroquine (CQ) and 3-methyladenine (3-MA), or silencing the autophagy-related genes (autophagy-related gene 5, autophagy-related gene 7), the inhibition of 5-FU to proliferation and the viability of GBC-SD cell were measured. And the apoptotic rate and cell cycle of GBC-SD cell were analyzed. RESULTS: Blocking of autophagy by pharmacological (CQ, 3-MA) or genetic (siRNA) means induced cell death in GBC-SD cell pre-treated with 5-FU.Furthermore, 5-FU treatment resulted in a general increase of apoptotic rate and G0/G1 arrest of GBC cells. And such an effect was potentiated by a pre-treatment of CQ. CONCLUSION: Autophagy in GBC-SD cell is induced by DNA damaging agent 5-fluorouracil.While in combination with CQ pre-treatment, the cytotoxicity of 5-fluorouracil becomes potentiated.

Suppression of autophagy by chloroquine sensitizes 5-fluorouracil-mediated cell death in gallbladder carcinoma cells.

Autophagy1 is a complex of adaptive cellular response that enhances cancer cell survival in the face of cellular stresses such as chemothery. Here we show that in human gallbladder carcinoma (GBC) cells lines, SGC-996 and GBC-SD, autophagy is induced by the DNA damaging agent 5-fluorouracil (5-FU). While in combination with the pre-treatment of chloroquine (CQ), a inhibitor of autophagy, the inhibition of 5-FU to the proliferation and viability of GBC cells was potentiated. Furthermore, 5-FU treatment resulted in a general increase of the apoptotic rate and G0/G1 arrest of GBC cells, and the effect was potentiated by CQ pre-treatment. Since 5-FU induced autophagy in GBC cells, and CQ inhibited autophagy, our findings suggest a possible mechanism that CQ inhibited 5-FU-induced autophagy, which modified the cytotoxicity of 5-FU. The combination therapy of CQ and 5-FU should be considered as an effective strategy for the treatment of gallbladder carcinoma.