Transcription factor EB modulates the homeostasis of reactive oxygen species in intestinal epithelial cells to alleviate inflammatory bowel disease

Transcription factor EB (TFEB), a master lysosomal biogenesis and autophagy regulator, is crucial for cellular homeostasis, and its abnormality is related to diverse inflammatory diseases. Genetic variations in autophagic genes are associated with susceptibility to inflammatory bowel disease (IBD); however, little is known about the role and mechanism of TFEB in disease pathogenesis. In this study, we found that the genetic deletion of TFEB in mouse intestinal epithelial cells (IEC) caused intestinal barrier dysfunction, leading to increased susceptibility to experimental colitis. Mechanistically, TFEB functionally protected IEC in part through peroxisome proliferator-activated receptor gamma coactivator 1alpha (TFEB-PGC1α axis) induction, which consequently suppressed reactive oxygen species. TFEB can directly regulate PGC-1α transcription to control antioxidation level. Notably, TFEB expression is impaired and downregulated in the colon tissues of IBD patients. Collectively, our results indicate that intestinal TFEB participates in oxidative stress regulation and attenuates IBD progression.

[Advances in molecular mechanism and treatment of chronic mucus hypersecretion]

Chronic obstructive pulmonary disease (COPD) is one of the chronic diseases with high morbidity and mortality in China, which imposes heavy economic burden on society. Research has shown that chronic mucus hypersecretion (CMH) is an independent risk factor for persistent clinical symptoms, poor quality of life, rapid decline in lung function, acute exacerbation and increased hospitalization rate in COPD patients. CMH is a clinical phenotype of COPD with specific pathological and physiological changes. At present, the formation mechanism of CMH is not clear. There is a lack of specific and effective targeted treatments. This article aimed to review the latest research findings on CMH at home and abroad from the overview, impact on COPD patients, molecular mechanisms of formation, current treatment status and progress, and discuss potential targets for CMH treatment, to provide new ideas and directions for improving CMH and treating COPD.

[Research progress of chronic obstructive pulmonary disease in young people and pre-COPD]

Conventional wisdom holds that the onset of chronic obstructive pulmonary disease (COPD) is usually in older people. However, with extended follow-up in large cohort studies, the trajectory of lung function development has been gradually delineated, indicating that the decline of lung function may originate early in life. In addition, a large number of studies have shown that people with chronic respiratory symptoms, pulmonary imaging changes and abnormal lung physiology, but not in line with pulmonary function diagnosis of COPD, tend to develop COPD in the future and may have a worse prognosis, suggesting the necessity of early intervention. The GOLD 2022 report proposes a series of terms related to COPD, including COPD in young people and pre-COPD, opening up new opportunities for the prevention, early diagnosis and treatment of COPD. These concepts also guide the study design of the biological mechanism of COPD and the trajectory of disease progression. This article reviews the research progress of COPD in young people and pre-COPD to attract more attention in clinical practice.

Extracellular vesicle-mediated intercellular and interorgan crosstalk of pancreatic islet in health and diabetes

Diabetes mellitus (DM) is a systemic metabolic disease with high mortality and morbidity. Extracellular vesicles (EVs) have emerged as a novel class of signaling molecules, biomarkers and therapeutic agents. EVs-mediated intercellular and interorgan crosstalk of pancreatic islets plays a crucial role in the regulation of insulin secretion of β-cells and insulin action in peripheral insulin target tissues, maintaining glucose homeostasis under physiological conditions, and it's also involved in pathological changes including autoimmune response, insulin resistance and β-cell failure associated with DM. In addition, EVs may serve as biomarkers and therapeutic agents that respectively reflect the status and improve function and viability of pancreatic islets. In this review, we provide an overview of EVs, discuss EVs-mediated intercellular and interorgan crosstalk of pancreatic islet under physiological and diabetic conditions, and summarize the emerging applications of EVs in the diagnosis and treatment of DM. A better understanding of EVs-mediated intercellular and interorgan communication of pancreatic islets will broaden and enrich our knowledge of physiological homeostasis maintenance as well as the development, diagnosis and treatment of DM.

Biodegradable and Antioxidant DNA Hydrogel as a Cytokine Delivery System for Diabetic Wound Healing

Impaired diabetic wound healing is associated with the persistence of chronic inflammation and excessive oxidative stress, which has become one of the most serious clinical challenges. Wound dressings with anti-inflammatory and reactive oxygen species (ROS)-scavenging properties are desirable for diabetic wound treatment. In this study, a shape-adaptable, biodegradable, biocompatible, antioxidant, and immunomodulatory interleukin-33 (IL-33)-cytogel is developed by encapsulating IL-33 into physically cross-linked DNA hydrogels and used as wound dressings to promote diabetic wound healing. The porous microstructures and biodegradable properties of the IL-33-cytogel ensure the local sustained-release of IL-33 in the wound area, where the sustained-release of IL-33 is maintained for at least 7 days. IL-33-cytogel can induce local accumulation of group 2 innate lymphoid cells (ILC2s) and regulatory T cells (Tregs), as well as M1-to-M2 transition at the wound sites. Additionally, the antioxidant and biocompatible characteristics of DNA hydrogels promote the scavenging of intracellular ROS without affecting cell viability. As a result, local inflammation in the diabetic wound area is resolved upon IL-33-cytogel treatment, which is accompanied by improved granulation tissue regeneration and accelerated wound closure. This study demonstrates a promising strategy in tissue engineering and regenerative medicine by incorporating DNA hydrogels and cytokine immunotherapy for promoting diabetic wound healing.

Adiponectin gene therapy prevents islet loss after transplantation

Significant pancreatic islet dysfunction and loss shortly after transplantation to the liver limit the widespread implementation of this procedure in the clinic. Nonimmune factors such as reactive oxygen species and inflammation have been considered as the primary driving force for graft failure. The adipokine adiponectin plays potent roles against inflammation and oxidative stress. Previous studies have demonstrated that systemic administration of adiponectin significantly prevented islet loss and enhanced islet function at post‐transplantation period. In vitro studies indicate that adiponectin protects islets from hypoxia/reoxygenation injury, oxidative stress as well as TNF‐α‐induced injury. By applying adenovirus mediated transfection, we now engineered islet cells to express exogenous adiponectin gene prior to islet transplantation. Adenovirus‐mediated adiponectin transfer to a syngeneic suboptimal islet graft transplanted under kidney capsule markedly prevented inflammation, preserved islet graft mass and improved islet transplant outcomes. These results suggest that adenovirus‐mediated adiponectin gene therapy would be a beneficial clinical engineering approach for islet preservation in islet transplantation.

Plant green pigment of chlorophyllin attenuates inflammatory bowel diseases by suppressing autophagy activation in mice

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are intestinal complications characterized by chronic inflammation, autophagy abnormality, and lysosomal stress, which are derived from genetic predisposition and environmental risk factors. It is generally precepted that dietary green vegetable is beneficial for physiological homeostasis. In this study, we found that dextran sulfate sodium (DSS)-induced colitis and altered intestinal epithelia in mice were attenuated by oral administration of chlorophyllin (CHL), a water-soluble derivate of chlorophyll. In DSS-treated mice, autophagy was persistently activated in intestinal tissues and associated with bowel disorders. Conversely, supplement of CHL in diet or gavage suppressed intestinal inflammation, downregulated autophagy flux in intestinal tissue, and relieved endoplasmic reticulum stress. In vitro studies show that CHL could activate Akt and mTOR pathways, leading to downregulation of autophagic and lysosomal flux. Thus, consumption of green vegetables and chlorophyllin may be beneficial for IBD recovery in part through alleviation of inflammation and autolysosomal flux.NEW & NOTEWORTHY Inflammatory bowel disease (IBD) is a chronic and recurrent gastrointestinal disease, while the etiology remains poorly understood. Dietary composition and lifestyle are crucial for pathogenesis and progression of IBD. In this study, we observed that autophagy in the intestinal tissue was persistently activated in IBD mice. Chlorophyllin (CHL), a water-soluble derivate of chlorophyll, can attenuate colitis by regulating autophagy and inflammation. Thus, consumption of green vegetables and chlorophyllin may be beneficial for IBD recovery.

Physically Cross-Linked DNA Hydrogel-Based Sustained Cytokine Delivery for In Situ Diabetic Alveolar Bone Rebuilding

The development of a biodegradable and shape-adaptable bioscaffold that can enhance local cytokine retention and bioactivity is essential for the application of immunotherapy in periodontal diseases. Here, we report a biodegradable, anti-inflammatory, and osteogenic ILGel that uses a physically cross-linked DNA hydrogel as a soft bioscaffold for the long-term sustained release of cytokine interleukin-10 (IL-10) to accelerate diabetic alveolar bone rebuilding. Porous microstructures of ILGel favored the encapsulation of IL-10 and maintained IL-10 bioactivity for at least 7 days. ILGel can be gradually degraded or hydrolyzed under physiological conditions, avoiding the potential undesired side effects on dental tissues. Long-term sustained release of bioactive IL-10 from ILGel not only promoted M2 macrophage polarization and attenuated periodontal inflammation but also triggered osteogenesis of mesenchymal stem cells (MSCs), leading to accelerated alveolar bone formation and healing of alveolar bone defects under diabetic conditions in vivo. ILGel treatment significantly accelerated the defect healing rate of diabetic alveolar injury up to 93.42 ± 4.6% on day 21 post treatment compared to that of free IL-10 treatment (63.30 ± 7.39%), with improved trabecular architectures. Our findings imply the potential application of the DNA hydrogel as the bioscaffold for cytokine-based immunotherapy in diabetic alveolar bone injury and other periodontal diseases.

Vitamin D and Pancreatitis: A Narrative Review of Current Evidence

Emerging research indicates that vitamin D metabolic disorder plays a major role in both acute pancreatitis (AP) and chronic pancreatitis (CP). This has been demonstrated by studies showing that vitamin D deficiency is associated with pancreatitis and its anti-inflammatory and anti-fibrotic effects by binding with the vitamin D receptor (VDR). However, the role of vitamin D assessment and its management in pancreatitis remains poorly understood. In this narrative review, we discuss the recent advances in our understanding of the molecular mechanisms involved in vitamin D/VDR signaling in pancreatic cells; the evidence from observational studies and clinical trials that demonstrate the connection among vitamin D, pancreatitis and pancreatitis-related complications; and the route of administration of vitamin D supplementation in clinical practice. Although further research is still required to establish the protective role of vitamin D and its application in disease, evaluation of vitamin D levels and its supplementation should be important strategies for pancreatitis management according to currently available evidence.

Alterations of the Gut Microbiome and Fecal Metabolome in Colorectal Cancer: Implication of Intestinal Metabolism for Tumorigenesis

Objective: The gut microbiota and its metabolites are important for host physiological homeostasis, while dysbiosis is related to diseases including the development of cancers such as colorectal cancer (CRC). In this study, we characterized the relationship of an altered gut microbiome with the fecal metabolome in CRC patients in comparison with volunteers having a normal colorectal mucous membrane (NC).

Methods: The richness and composition of the microbiota in fecal samples of 30 CRC patients and 36 NC controls were analyzed through 16S rRNA gene sequencing, and the metabolome was determined by ultra-performance liquid chromatography coupled to tandem mass spectrometry. Spearman correlation analysis was to determine the correlation between the gut microbiome and fecal metabolome in CRC patients.

Results: There were significant alterations in the gut microbiome and fecal metabolome in CRC patients compared with NC controls. Bacteroidetes, Firmicutes, Actinobacteriota, and Proteobacteria dominated the gut microbial communities at the phylum level in both groups. Compared with NC controls, CRC patients had a lower frequency of Blautia and Lachnospiracaea but a higher abundance of Bacteroides fragilis and Prevotella. Regarding the fecal metabolome, twenty-nine metabolites were identified as having significantly changed, showing increased levels of adrenic acid, decanoic acid, arachidonic acid, and tryptophan but a reduction in various monosaccharides in the fecal samples of CRC patients. Moreover, increased abundance of Bacteroides fragilis was strongly associated with decreased levels of monosaccharides, while Blautia was positively associated with the production of monosaccharides in the fecal samples.

Conclusion: These results highlight alterations of gut microbiota in association with certain metabolites in CRC progression, implying potential diagnostic and intervention potential for CRC.

The unique pancreatic stellate cell gene expression signatures are associated with the progression from acute to chronic pancreatitis

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Early recognition of chronic pancreatitis (CP) is still lacking. In the setting of CP injury, activated pancreatic stellate cell (PSC) is the central mediator of pancreatic fibrosis. We systematically define highly and uniquely expressed PSC genes and show that these genes are enriched in pancreatic diseases.

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Unresolved or recurrent injury causes dysregulation of biological process following AP, which would cause CP. We demonstrated subset genes that may be associated with the progression from AP to CP. Furthermore, SPARC was identified as a candidate marker for the disease progression.

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Increased expression of SPARC and canonical PSC genes were verified during AP recovery, especially in recurrent AP mice models.

Chronic pancreatitis (CP) is characterized by irreversible fibro-inflammatory changes induced by pancreatic stellate cell (PSC). Unresolved or recurrent injury causes dysregulation of biological process following AP, which would cause CP. Here, we systematically identify genes whose expressions are unique to PSC by comparing transcriptome profiles among total pancreas, pancreatic stellate, acinar, islet and immune cells. We then identified candidate genes and correlated them with the pancreatic disease continuum by performing intersection analysis among total PSC and activated PSC genes, and genes persistently differentially expressed during acute pancreatitis (AP) recovery. Last, we examined the association between candidate genes and AP, and substantiated their potential as biomarkers in experimental AP and recurrent AP (RAP) models. A total of 68 genes were identified as highly and uniquely expressed in PSC. The PSC signatures were highly enriched with extracellular matrix remodeling genes and were significantly enriched in AP pancreas compared to healthy control tissues. Among PSC signature genes that comprised a fibrotic phenotype, 10 were persistently differentially expressed during AP recovery. SPARC was determined as a candidate marker for the pancreatic disease continuum, which was not only persistently differentially expressed even five days after AP injury, but also highly expressed in two clinical datasets of CP. Sparc was also validated as highly elevated in RAP compared to AP mice. This work highlights the unique transcriptional profiles of PSC. These PSC signatures’ expression may help to identify patients with high risk of AP progression to CP.

Green Plant Pigment, Chlorophyllin, Ameliorates Non-alcoholic Fatty Liver Diseases (NAFLDs) Through Modulating Gut Microbiome in Mice

Non-alcoholic fatty liver diseases (NAFLDs) along with metabolic syndrome and Type-2 diabetes (T2D) are increasingly prevalent worldwide. Without an effective resolution, simple hepatic steatosis may lead to non-alcoholic steatohepatitis (NASH), characterized by hepatocyte damage, chronic inflammation, necrosis, fatty degeneration, and cirrhosis. The gut microbiome is vital for metabolic homeostasis. Conversely, dysbiosis contributes to metabolic diseases including NAFLD. Specifically, diet composition is critical for the enterotype of gut microbiota. We reasoned that green pigment rich in vegetables may modulate the gut microbiome for metabolic homeostasis. In this study, C57BL/6 mice under a high fat diet (HFD) were treated with sodium copper chlorophyllin (CHL), a water-soluble derivative of chlorophyll, in drinking water. After 28 weeks of HFD feeding, liver steatosis was established accompanied by gut microbiota dysbiosis, intestinal impairment, endotoxemia, systemic inflammation, and insulin resistance. Administration of CHL effectively alleviated systemic and intestinal inflammation and maintained tight junction in the intestinal barrier. CHL rebalanced gut microbiota in the mice under high fat feeding and attenuated hepatic steatosis, insulin resistance, dyslipidemia, and reduced body weight. Fecal flora transplants from the CHL-treated mice ameliorated steatosis as well. Thus, dietary green pigment or the administration of CHL may maintain gut eubiosis and intestinal integrity to attenuate systemic inflammation and relieve NASH.

A DNA Nanoraft-Based Cytokine Delivery Platform for Alleviation of Acute Kidney Injury

Cytokine immunotherapy represents an attractive strategy to stimulate robust immune responses for renal injury repair in ischemic acute kidney injury (AKI). However, its clinical application is hindered by its nonspecificity to kidney, short circulation half-life, and severe side effects. An ideal cytokine immunotherapy for AKI requires preferential delivery of cytokines with accurate dosage to the kidney and sustained-release of cytokines to stimulate the immune responses. Herein, we developed a DNA nanoraft cytokine by precisely arranging interleukin-33 (IL-33) nanoarray on rectangle DNA origami, through which IL-33 can be preferentially delivered to the kidney for alleviation of AKI. A nanoraft carrying precisely quantified IL-33 predominantly accumulated in the kidney for up to 48 h. Long-term sustained-release of IL-33 from nanoraft induced rapid expansion of type 2 innate lymphoid cells (ILC 2s) and regulatory T cells (Tregs) and achieved better treatment efficiency compared to free IL-33 treatment. Thus, our study demonstrates that a nanoraft can serve as a structurally well-defined delivery platform for cytokine immunotherapy in ischemic AKI and other renal diseases.

[Protective effect of vitamin D in mice with acute liver failure]

Objective: To explore the protective effect of vitamin D in acute liver failure through a mouse model. Methods: Acute liver failure was induced by combining D-galactosamine (D-GalN) lipopolysaccharide (LPS) to observe the effect of long-term vitamin D deficiency on liver injury and inflammatory signals in a mouse model. Acute liver failure was induced by thioacetamide (TAA) to observe the effect of vitamin D deficiency on the survival rate, and further high-dose of vitamin D supplementation protective effect was determined in a mouse model. Liver function was evaluated by measuring serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and liver inflammation by hematoxylin-eosin staining. The expressions of tumor necrosis factor (TNF-α), interleukin (IL) -1β, NOD-like receptor family, pyrin domain containing 3 (NLRP-3), chemokines (CCL2, CXCL1 and CXCL2), etc. in liver tissues were detected by RT-qPCR. The quantitation of macrophages in liver tissue was detected by immunohistochemistry. The comparison between groups were performed by t-test. The survival curve was analyzed by log-rank (Mantel-Cox) test. Results: Long-term vitamin D deficiency had increased acute liver failure sensitivity in mice, which was manifested by increased blood cell extravasation, massive necrosis of parenchymal cells, up-regulation of TNF-α, IL-1β, and NLRP-3 mRNA expression (P < 0.05), and increased macrophages quantitation (P < 0.05) in liver tissues. At the same time, vitamin D deficiency had increased the mice mortality rate because of liver injury (P < 0.01). On the contrary, pre-administration of high dose of vitamin D (100 IU/g) had significantly reduced liver injury, inhibited ALT and AST rise (P < 0.01), alleviated liver necrosis, and down-regulated the mRNA expression of inflammatory factors in liver tissues (P < 0.05). Conclusion: Mouse model shows that long-term vitamin D deficiency can aggravate drug-induced acute liver failure and reduce survival rates. Furthermore, high-dose of vitamin D has a certain hepatoprotective effect, which can significantly improve liver necrosis condition and inhibit inflammation. Therefore, adequate vitamin D can retain liver physiological balance to resist liver injury.

Hepatitis B Virus X Protein (HBx) Suppresses Transcription Factor EB (TFEB) Resulting in Stabilization of Integrin Beta 1 (ITGB1) in Hepatocellular Carcinoma Cells

Hepatitis B virus (HBV) infection is a major etiological risk for the incidence of hepatocellular carcinoma (HCC), and HBV X protein (HBx) is essential for oncogenic transformation. It is not known that if HBx can sabotage the lysosomal system for transformation and tumorigenesis, or its mechanism if it does have an effect. Examining clinical data, we observed that the downregulation of lysosomal components and transcription factor EB (TFEB) was associated with a poor prognosis of HCC patients. In HCC cells, we found that expression of HBx suppressed TFEB, impaired biogenesis of autophagic-lysosome, and promoted cellular dissemination. HBx mediated downregulation of TFEB led to impairment of autophagic/lysosomal biogenesis and flux, and consequently, accumulation of integrin beta 1 (ITGB1) for motility of HCC cells. Conversely, TFEB, in a steady-state condition, through induction of lysosomal biogenesis restrained ITGB1 levels and limited mobility of HCC cells. Specifically, overexpression of TFEB upregulated and activated the cysteine proteases including cathepsin L (CTSL) to degrade ITGB1. Conversely, expression of cystatin A (CSTA) or cystatin B (CSTB), the cellular inhibitors of lysosomal cysteine proteinases, spared ITGB1 from degradation and promoted dissemination of HCC cells. Taken together, this study suggests a potential mechanism for HBV-mediated malignancy, showing that HBx mediated downregulation of TFEB leads to accumulation of ITGB1 for HCC cell migration.

[Effect of bone marrow mononuclear cell transplantation on miRNA-21 and miRNA-155 expression in mice with ulcerative colitis]

Objective: To investigate the effect of bone marrow mononuclear cell transplantation on the expression of miRNA-21 and miRNA-155 in mice with ulcerative colitis(UC). Methods: Healthy and clean KM mice aged 6-8 weeks were randomly divided into transplantation group, model group and normal control group with 15 mice in each group. In the transplantation group and model group, dextran sodium sulfate (DSS) was used to establish the model for 24 h. The mice in the transplantation group were injected with 0.4 ml of 4 ', 6-diaminol-2-phenylindole (DAPI) -labeled P3-BM-MNCs cell suspension (3.2×10(6) cells/ml), and the mice in the model group and the normal control group were injected with 0.4 ml phosphate buffer (PBS).UC disease activity index (DAI) was used to test the general condition of mice; HE staining was used to observe the pathological changes of colon tissue; Real-time quantitative PCR was used to detect the expression of miRNA-21 and miRNA-155 mRNA. Results: DAI scores of normal control group, model group and transplantation group were 0 (0,1), 3.1 (2.8,3.3) and 2.7 (2.4,3.1),respectively. Compared with normal control group, the DAI score of model group and transplantation group was higher (P<0.05), and the DAI score of transplantation group was lower than that of model group (P<0.05). The gross scores of tissue injury in normal control group, model group and transplantation group were 0 (0, 1), 3 (3, 4) and 1 (1, 2), respectively,and the pathological scores of tissue injury were 0 (0, 1), 16 (12, 16) and 6 (6, 8), respectively,compared with the normal control group. The tissue injury score of the model group and the transplantation group was higher (P<0.05), and the tissue injury score of the transplantation group was lower than that of the model group (P<0.05). The expression levels of miRNA-21 mRNA in normal control group, model group and transplantation group were 0.87±0.15, 2.38±0.29 and 1.59±0.32, respectively, and the expression levels of miRNA-155 mRNA were 1.87±0.46, 7.38±1.97 and 3.92±0.84, respectively, compared with the normal control group, the expression of miRNA-21 and miRNA-155 mRNA in the model group and transplantation group was higher (P<0.01), the expression of miRNA-21 and miRNA-155 mRNA in the transplantation group was lower than that of the model group (P<0.05). Conclusion: Bone marrow mononuclear cell transplantation can improve the histopathological and DAI scores of mice with UC, which may be related to the down-regulation of miRNA-21 and miRNA-155 mRNA expression.

Liver Injury Impaired 25-Hydroxylation of Vitamin D Suppresses Intestinal Paneth Cell defensins, leading to Gut Dysbiosis and Liver Fibrogenesis

Vitamin D deficiency is co-prevalent with various liver diseases including cirrhosis, while the underlying mechanism remains elusive. Vitamin D receptor (VDR) is abundantly expressed in the distal region of small intestine, where the Paneth cells are enriched, suggesting that vitamin D signaling may modulates the intestinal Paneth cells and their production of defensins to restrain microbiome growth in the small intestine. In this study we found that in carbon tetrachloride-induced liver injury, hepatic 25-hydroxylation of vitamin D was impaired, leading to down regulated expression of Paneth cell fensins in the small intestine, gut dysbiosis, and endotoxinemia. While intraperitoneal injection of endotoxin (lipopolysaccharides) alone did not elicit liver fibrosis, it exacerbated the carbon tetrachloride initiated liver fibrogenesis. Oral gavage of synthetic Paneth cell alpha-defensin 5 (DEFA5) restored the homeostasis of gut microbiota, reduced endotoxemia, relieved liver inflammation, and ameliorated liver fibrosis. Likewise, Cholestyramine, cationic resin that can sequestrate endotoxin in the intestine, attenuated the liver fibrosis as well. Fecal transplant of the microbes derived from the DEFA5-treated donors improved liver fibrosis in the recipient mice. The intestinal Vdrconditional knockout mice exhibited reduction of Paneth cell defensins and lysozyme production, and worsened liver injury and fibrogenesis. Thus, liver injury impairs synthesis of 25(OH)VD3, which consequently impedes the Paneth cells functions in the small intestine, leading to gut dysbiosis for liver fibrogenesis.

Vitamin D signaling maintains intestinal innate immunity and gut microbiota: potential intervention for metabolic syndrome and NAFLD

A lack of sunlight exposure, residence in the northern latitudes, and dietary vitamin D insufficiency are coprevalent with metabolic syndrome (MetS), Type 2 diabetes (T2D), and nonalcoholic fatty liver diseases (NAFLD), implying a potential causality and underlying mechanism. Whether vitamin D supplementation or treatment can improve these disorders is controversial, in part, because of the absence of large-scale trials. Experimental investigations, on the other hand, have uncovered novel biological functions of vitamin D in development, tumor suppression, and immune regulation, far beyond its original role as a vitamin that maintained calcium homeostasis. While the large intestine harbors massive numbers of microbes, the small intestine has a minimal quantity of bacteria, indicating the existence of a gating system located in the distal region of the small intestine that may restrain bacterial translocation to the small intestine. Vitamin D receptor (VDR) was found to be highly expressed at the distal region of small intestine, where the vitamin D signaling promotes innate immunity, including the expression of α-defensins by Paneth cells, and maintains the intestinal tight junctions. Thus, a new hypothesis is emerging, indicating that vitamin D deficiency may impair the intestinal innate immunity, including downregulation of Paneth cell defensins, leading to bacterial translocation, endotoxemia, systemic inflammation, insulin resistance, and hepatic steatosis. Here, we review the studies for vitamin D for innate immunity and metabolic homeostasis, and we outline the clinical trials of vitamin D for mitigating MetS, T2D, and NAFLD.

Lost or Forgotten: The nuclear cathepsin protein isoforms in cancer

While research into the role of cathepsins has been progressing at an exponential pace over the years, research into their respective isoform proteins has been less frenetic. In view of the functional and biological potential of such protein isoforms in model systems for cancer during their initial discovery, much later they have offered a new direction in the field of cathepsin basic and applied research. Consequently, the analysis of such isoforms has laid strong foundations in revealing other important regulatory aspects of the cathepsin proteins in general. In this review article, we address these key aspects of cathepsin isoform proteins, with particular emphasis on how they have shaped what is now known in the context of nuclear cathepsin localization and what potential these hold as nuclear-based therapeutic targets in cancer.

Pathway crosstalk analysis in prostate cancer based on protein-protein network data

Prostate cancer (PCa) is one of the major leading cause in men and no effective biomarkers or therapy have been approved for it to date. This study aimed to explore the molecular mechanisms and identify the potential molecular biomarkers of PCa. The microarray profile GSE38241 including 18 prostate cancer metastasis and 21 normal prostate samples was retrieved from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified by Limma. DEGs functions were investigated by Gene Ontology (GO) and pathway enrichment analysis. Moreover, protein-protein interaction (PPI) network of DEGs was constructed, followed by functional analysis of modules. Additionally, pathway crosstalk network was constructed by integrating PPI network and Kyoto encyclopedia of genes and genomes (KEGG) pathways. Totally, 334 up - and 703 down-regulated DEGs were identified. The functions of up-regulated DEGs were significantly enriched in GO terms of cell cycle phase and cell cycle process. While down-regulated DEGs mainly participated in actin filament-based process. Among these pathways in the pathway crosstalk network, T cell receptor signaling pathway, chemokine signaling pathways, endometrial cancer and glioma were found to play critical roles during PC progression. Cell division cycle 45 (CDC45), baculoviral IAP repeat containing 5 (BIRC5) and cell division cycle associated 5 (CDCA5) may be useful markers for predicting tumor metastasis and therapeutic targets for the treatment of PCa patients. Moreover, the pathway crosstalk network provides the groundwork that targeting multiple pathways might be more effective than targeting one pathway alone.

Chlorophyllin Modulates Gut Microbiota and Inhibits Intestinal Inflammation to Ameliorate Hepatic Fibrosis in Mice

Liver fibrosis is an abnormal wound healing response and a common consequence of chronic liver diseases from infection or alcohol/xenobiotic exposure. At the cellular level, liver fibrosis is mediated by trans-differentiation of hepatic stellate cells (HSCs), which is driven by persistent hepatic and systemic inflammation. However, impaired enterohepatic circulation and gut dysbiosis may indirectly contribute to the liver fibrogenesis. The composition of the gut microbiota depends on diet composition and host factors. In this study, we examined chlorophyllin, derived from green pigment chlorophyll, on gut microbiota, the intestinal mucosal barrier, and liver fibrosis. BALB/c mice received carbon tetrachloride through intraperitoneal injection to induce liver fibrosis and chlorophyllin was administrated in drinking water. The effects of chlorophyllin on liver fibrosis were evaluated for (1) survival rate, (2) hepatic morphologic analysis, (3) inflammatory factors in both the small intestine and liver, and (4) gut microbiota. Our results indicate that oral administration of chlorophyllin could attenuate intestinal and hepatic inflammation and ameliorate liver fibrosis. Importantly, oral administration of chlorophyllin promptly rebalanced the gut microbiota, exhibiting down-regulation of the phylum Firmicutes and up-regulation of the phylum Bacteroidetes. In vitro experiments on intestinal epithelial cells showed that chlorophyllin exposure could inhibit NF-κB pathway via IKK-phosphorylation suppression. In conclusion, this study demonstrates potential application of chlorophyllin to regulate the intestinal microbiota and ameliorate hepatic fibrosis.

Alternation of Gut Microbiota in Patients with Pulmonary Tuberculosis

One-third of the world's population has been infected with Mycobacterium tuberculosis (M. tuberculosis), a primary pathogen of the mammalian respiratory system, while about 10% of latent infections progress to active tuberculosis (TB), indicating that host and environmental factors may determine the outcomes such as infection clearance/persistence and treatment prognosis. The gut microbiota is essential for development of host immunity, defense, nutrition and metabolic homeostasis. Thus, the pattern of gut microbiota may contribute to M. tuberculosis infection and prognosis. In current study we characterized the differences in gut bacterial communities in new tuberculosis patients (NTB), recurrent tuberculosis patients (RTB), and healthy control. The abundance-based coverage estimator (ACE) showed the diversity index of the gut microbiota in the patients with recurrent tuberculosis was increased significantly compared with healthy controls (p < 0.05). At the phyla level, Actinobacteria and Proteobacteria, which contain many pathogenic species, were significantly enriched in the feces RTB patients. Conversely, phylum Bacteroidetes, containing a variety of beneficial commensal organisms, was reduced in the patients with the recurrent tuberculosis compared to healthy controls. The Gram-negative genus Prevotella of oral origin from phylum of Bacteroidetes and genus Lachnospira from phylum of Firmicutes were significantly decreased in both the new and recurrent TB patient groups, compared with the healthy control group (p < 0.05). We also found that there was a positive correlation between the gut microbiota and peripheral CD4+ T cell counts in the patients. This study, for the first time, showed associations between gut microbiota with tuberculosis and its clinical outcomes. Maintaining eubiosis, namely homeostasis of gut microbiota, may be beneficial for host recovery and prevention of recurrence of M. tuberculosis infection.

M2-like macrophages in the fibrotic liver protect mice against lethal insults through conferring apoptosis resistance to hepatocytes

Acute injury in the setting of liver fibrosis is an interesting and still unsettled issue. Most recently, several prominent studies have indicated the favourable effects of liver fibrosis against acute insults. Nevertheless, the underlying mechanisms governing this hepatoprotection remain obscure. In the present study, we hypothesized that macrophages and their M1/M2 activation critically involve in the hepatoprotection conferred by liver fibrosis. Our findings demonstrated that liver fibrosis manifested a beneficial role for host survival and apoptosis resistance. Hepatoprotection in the fibrotic liver was tightly related to innate immune tolerance. Macrophages undertook crucial but divergent roles in homeostasis and fibrosis: depleting macrophages in control mice protected from acute insult; conversely, depleting macrophages in fibrotic liver weakened the hepatoprotection and gave rise to exacerbated liver injury upon insult. The contradictory effects of macrophages can be ascribed, to a great extent, to the heterogeneity in macrophage activation. Macrophages in fibrotic mice exhibited M2-preponderant activation, which was not the case in acutely injured liver. Adoptive transfer of M2-like macrophages conferred control mice conspicuous protection against insult. In vitro, M2-polarized macrophages protected hepatocytes against apoptosis. Together, M2-like macrophages in fibrotic liver exert the protective effects against lethal insults through conferring apoptosis resistance to hepatocytes.

Cationic Polystyrene Resolves Nonalcoholic Steatohepatitis, Obesity, and Metabolic Disorders by Promoting Eubiosis of Gut Microbiota and Decreasing Endotoxemia

A pandemic of metabolic diseases, consisting of type 2 diabetes, nonalcoholic fatty liver disease, and obesity, has imposed critical challenges for societies worldwide, prompting investigation of underlying mechanisms and exploration of low-cost and effective treatment. In this report, we demonstrate that metabolic disorders in mice generated by feeding with a high-fat diet without dietary vitamin D can be prevented by oral administration of polycationic amine resin. Oral administration of cholestyramine, but not the control uncharged polystyrene, was able to sequester negatively charged bacterial endotoxin in the gut, leading to 1) reduced plasma endotoxin levels, 2) resolved systemic inflammation and hepatic steatohepatitis, and 3) improved insulin sensitivity. Gut dysbiosis, characterized as an increase of the phylum Firmicutes and a decrease of Bacteroidetes and Akkermansia muciniphila, was fully corrected by cholestyramine, indicating that the negatively charged components in the gut are critical for the dysbiosis. Furthermore, fecal bacteria transplant, derived from cholestyramine-treated animals, was sufficient to antagonize the metabolic disorders of the recipient mice. These results indicate that the negatively charged components produced by dysbiosis are critical for biogenesis of metabolic disorders and also show a potential application of cationic polystyrene to treat metabolic disorders through promoting gut eubiosis.

M2-like Kupffer cells in fibrotic liver may protect against acute insult

AIM

To investigate the mechanism of hepatoprotection conferred by liver fibrosis through evaluating the activation phenotype of kupffer cells.

METHODS

Control and fibrotic mice were challenged with a lethal dose of D-GalN/lipopolysaccharide (LPS), and hepatic damage was assessed by histology, serum alanine transferase (ALT) levels, and hepatic expression of HMGB1, a potent pro-inflammatory mediator. The localization of F4/80 (a surrogate marker of KCs), HMGB1, and type I collagen (Col-1) was determined by immunofluorescence staining. The phenotype of KCs was characterized by real-time PCR. KCs isolated from control or fibrotic mice were challenged with LPS or HMGB1 peptide, and HMGB1 translocation was analyzed.

RESULTS

Liver fibrosis protected mice against D-GalN/LPS challenge, as shown by improved hepatic histology and reduced elevation of ALT compared with the normal mice treated in the same way. This hepatoprotection was also accompanied by inhibition of HMGB1 expression in the liver. Co-localization of F4/80, HMGB1, and Col-1 was found in fibrotic livers, indicating the close relationship between KCs, HMGB1 and liver fibrosis. KCs isolated from fibrotic mice predominantly exhibited an M2-like phenotype. In vitro experiments showed that HMGB1 was localized in the nucleus of the majority of M2-like KCs and that the translocation of HMGB1 was inhibited following stimulation with LPS or HMGB1 peptide, while both LPS and HMGB1 peptide elicited translocation of intranuclear HMGB1 in KCs isolated from the control mice.

CONCLUSION

M2-like Kupffer cells in fibrotic liver may exert a protective effect against acute insult by inhibiting the translocation of HMGB1.

Cathepsin H-Mediated Degradation of HDAC4 for Matrix Metalloproteinase Expression in Hepatic Stellate Cells: Implications of Epigenetic Suppression of Matrix Metalloproteinases in Fibrosis through Stabilization of Class IIa Histone Deacetylases

In three-dimensional extracellular matrix, mesenchymal cells including hepatic stellate cells (HSCs) gain the ability to express matrix metalloproteinases (MMPs) on injury signals. In contrast, in myofibroblastic HSCs in fibrotic liver, many MMP genes are silenced into an epigenetically nonpermissive state. The mechanism by which the three-dimensional extracellular matrix confers the MMP genes into an epigenetically permissive state has not been well characterized. In continuation of previous work, we show here that the up-regulation of MMP genes is mediated through degradation of class IIa histone deacetylases (HDACs) by certain cysteine cathepsins (Cts). In three-dimensional extracellular matrix culture, CtsH, among other cysteine cathepsins, was up-regulated and localized as puncta in the nuclear and cytoplasmic compartments in a complex with HDAC4 for its degradation. Conversely, along with HSC trans-differentiation, CtsH and CtsL were progressively down-regulated, whereas HDAC4 was concurrently stabilized. The inhibition of cysteine cathepsins by specific proteinase inhibitors or chloroquine, which raises cellular pH, restored HDAC4. Recombinant CtsH could break down HDAC4 in the transfected cells and in vitro at acidic pH. In human cirrhotic liver, activated HSCs express high levels of class IIa HDACs but little CtsH. We propose that cysteine cathepsin-mediated degradation of class IIa HDACs plays a key role in the modulation of MMP expression/suppression and HSC functions in tissue injury and fibrosis.

Vitamin D Signaling through Induction of Paneth Cell Defensins Maintains Gut Microbiota and Improves Metabolic Disorders and Hepatic Steatosis in Animal Models

Metabolic syndrome (MetS), characterized as obesity, insulin resistance, and non-alcoholic fatty liver diseases (NAFLD), is associated with vitamin D insufficiency/deficiency in epidemiological studies, while the underlying mechanism is poorly addressed. On the other hand, disorder of gut microbiota, namely dysbiosis, is known to cause MetS and NAFLD. It is also known that systemic inflammation blocks insulin signaling pathways, leading to insulin resistance and glucose intolerance, which are the driving force for hepatic steatosis. Vitamin D receptor (VDR) is highly expressed in the ileum of the small intestine, which prompted us to test a hypothesis that vitamin D signaling may determine the enterotype of gut microbiota through regulating the intestinal interface. Here, we demonstrate that high-fat-diet feeding (HFD) is necessary but not sufficient, while additional vitamin D deficiency (VDD) as a second hit is needed, to induce robust insulin resistance and fatty liver. Under the two hits (HFD+VDD), the Paneth cell-specific alpha-defensins including α-defensin 5 (DEFA5), MMP7 which activates the pro-defensins, as well as tight junction genes, and MUC2 are all suppressed in the ileum, resulting in mucosal collapse, increased gut permeability, dysbiosis, endotoxemia, systemic inflammation which underlie insulin resistance and hepatic steatosis. Moreover, under the vitamin D deficient high fat feeding (HFD+VDD), Helicobacter hepaticus, a known murine hepatic-pathogen, is substantially amplified in the ileum, while Akkermansia muciniphila, a beneficial symbiotic, is diminished. Likewise, the VD receptor (VDR) knockout mice exhibit similar phenotypes, showing down regulation of alpha-defensins and MMP7 in the ileum, increased Helicobacter hepaticus and suppressed Akkermansia muciniphila. Remarkably, oral administration of DEFA5 restored eubiosys, showing suppression of Helicobacter hepaticus and increase of Akkermansia muciniphila in association with resolving metabolic disorders and fatty liver in the HFD+VDD mice. An in vitro analysis showed that DEFA5 peptide could directly suppress Helicobacter hepaticus. Thus, the results of this study reveal critical roles of a vitamin D/VDR axis in optimal expression of defensins and tight junction genes in support of intestinal integrity and eubiosis to suppress NAFLD and metabolic disorders.

Persistence of cirrhosis is maintained by intrahepatic regulatory T cells that inhibit fibrosis resolution by regulating the balance of tissue inhibitors of metalloproteinases and matrix metalloproteinases

Fibrosis is the result of the abnormal accumulation of the extracellular matrix and ineffective clearance of fibroplasia. CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) are immunosuppressive lymphocytes that are highly expressed in the fibrotic tissues and peripheral blood of patients with cirrhosis or hepatocellular carcinoma. The role of Tregs in the progression of liver fibrosis is not well understood. Our experiments reveal that abundant of Tregs was scattered around sites of fibroplasia. Conversely, the depletion of Tregs promoted the resolution of liver fibrosis. As a consequence of Tregs depletion, the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) was altered; mmp9 and timp1 were reduced, whereas mmp2 and mmp14 were enhanced. The mmp9/timp1, mmp13/timp1, and mmp14/timp2 ratios were significantly increased in association with fibrosis resolution. Kupffer cells (KCs) are the main source of MMP. We observed that when KCs were cocultured with Tregs, the Tregs were able to inhibit MMP expression of KCs even at a low ratio; and anti-transforming growth factor-β (TGF-β) significantly reversed the inhibition of Tregs on MMP. Meanwhile, we also found that after Tregs depletion, TGF-β levels decreased in the mice liver, unlike in fibrosis. Furthermore, double depletion of both KCs and Tregs did not cause fiber resolution in mice. Thus, our results demonstrate that the persistence of liver cirrhosis is maintained by increased Tregs in the sites of fibroplasia and the subsequent regulation of the MMP/TIMP balance and that the suppression of KC-mediated MMP expression contributed to the regulatory process.

Spontaneous liver fibrosis induced by long term dietary vitamin D deficiency in adult mice is related to chronic inflammation and enhanced apoptosis

Epidemiological studies have revealed an association between vitamin D deficiency and various chronic liver diseases. However, it is not known whether lack of vitamin D can induce spontaneous liver fibrosis in an animal model. To study this, mice were fed either a control diet or a vitamin D deficient diet (VDD diet). For the positive control, liver fibrosis was induced with carbon tetrachloride. Here we show, for the first time, that liver fibrosis spontaneously developed in mice fed the VDD diet. Long-term administration of a VDD diet resulted in necro-inflammation and liver fibrosis. Inflammatory mediators including tumor necrosis factor-α, interleulin-1, interleukin-6, Toll-like-receptor 4, and monocyte chemotactic protein-1 were up-regulated in the livers of the mice fed the VDD diet. Conversely, the expression of Th2/M2 markers such as IL-10, IL-13, arginase 1, and heme oxygenase-1 were down-regulated in the livers of mice fed the VDD diet. Transforming growth factor-β1 and matrix metalloproteinase 13, which are important for fibrosis, were induced in the livers of mice fed the VDD diet. Moreover, the VDD diet triggered apoptosis in the parenchymal cells, in agreement with the increased levels of Fas and FasL, and decreased Bcl2 and Bclx. Thus, long-term vitamin D deficiency can provoke chronic inflammation that can induce liver apoptosis, which consequently activates hepatic stellate cells to initiate liver fibrosis.

Vitamin D deficiency promotes nonalcoholic steatohepatitis through impaired enterohepatic circulation in animal model

Vitamin D deficiency (VDD) or insufficiency is recognized for its association with nonalcoholic steatohepatitis (NASH), whereas the underlying mechanism remains unknown. Using animal models, we found that vitamin D deficiency promoted the high-fat diet (HFD)-initiated simple steatosis into typical NASH, characterized by elevated hepatic inflammation and fat degeneration. The NASH derived from VDD + HFD was related to poor retention of bile acids in the liver and biliary tree, in line with downregulation of the ileal apical sodium-dependent bile acid cotransporter (iASBT). The impediment of hepatic bile acids by the VDD + HFD mice was related to increased expression of hepatic SREBP-1c and fatty acid synthase, suggesting that VDD may upregulate endogenous fatty acid synthesis into NASH through impaired enterohepatic circulation. Administration of 1,25(OH)2VD3 (calcitriol) corrected the NASH phenotypes in line with restoration of iASBT, promotion of bile filling in the biliary tree, suppression of hepatic lipogenesis, and inflammation. Moreover, administration of a bile acid-sequestering agent suppressed ileal fibroblast growth factor 15 expression, leading to increased iASBT expression to restore bile filling in the liver and biliary tree, which ameliorates steatosis and inflammation in the liver. These results suggest a novel mechanism for NASH development, by which VDD downregulates iASBT expression, resulting in a poor bile acid pool and elevation of hepatic lipogenesis and inflammation. In conclusion, vitamin D and bile acid sequestration may be explored as new strategies to treat or prevent NASH.

Prognostic value of M30/M65 for outcome of hepatitis B virus-related acute-on-chronic liver failure

AIM: To determine the prognostic value of circulating indicators of cell death in acute-on-chronic liver failure (ACLF) patients with chronic hepatitis B virus (HBV) infection as the single etiology.

METHODS: Full length and caspase cleaved cytokeratin 18 (detected as M65 and M30 antigens) represent circulating indicators of necrosis and apoptosis. M65 and M30 were identified by enzyme-linked immunosorbent assay in 169 subjects including healthy controls (n = 33), patients with chronic hepatitis B (CHB, n = 55) and patients with ACLF (n = 81). According to the 3-mo survival period, ACLF patients were defined as having spontaneous recovery (n = 33) and non-spontaneous recovery which included deceased patients and those who required liver transplantation (n = 48).

RESULTS: Both biomarker levels significantly increased gradually as liver disease progressed (for M65: P < 0.001 for all; for M30: control vs CHB, P = 0.072; others: P < 0.001 for all). In contrast, the M30/M65 ratio was significantly higher in controls compared with CHB patients (P = 0.010) or ACLF patients (P < 0.001). In addition, the area under receiver operating characteristic curve (AUC) analysis demonstrated that both biomarkers had diagnostic value (AUC ≥ 0.80) in identifying ACLF from CHB patients. Interestingly, it is worth noting that the M30/M65 ratio was significantly different between spontaneous and non-spontaneous recovery in ACLF patients (P = 0.032). The prognostic value of the M30/M65 ratio was compared with the Model for End-Stage Liver Disease (MELD) and Child-Pugh scores at the 3-mo survival period, the AUC of the M30/M65 ratio was 0.66 with a sensitivity of 52.9% and the highest specificity of 92.6% (MELD:AUC = 0.71; sensitivity, 79.4%; specificity, 63.0%; Child-Pugh: AUC = 0.77; sensitivity, 61.8%; specificity, 88.9%).

CONCLUSION: M65 and M30 are strongly associated with liver disease severity. The M30/M65 ratio may be a potential prognostic marker for spontaneous recovery in patients with HBV-related ACLF.

Restoration of intrahepatic regulatory T cells through MMP-9/13-dependent activation of TGF-β is critical for immune homeostasis following acute liver injury

During the acute liver injury, immune responses are provoked into eliciting inflammation in the acute phase. In the healing phase, the inflammation is terminated for wound healing and restoration of immune homeostasis. In this study, we sought to address how regulatory T cells (Tregs) are involved in the progression of liver injury and repair. In the acute phase, intrahepatic Tregs (CD4(+)FoxP3(+)Helios(+)) diminished promptly through apoptosis, which was followed by inflammation and tissue injury. In the healing phase, a new subset of Tregs (CD4(+)Foxp3(+)Helios(-)) was generated in correlation with the matrix metalloproteinase (MMP) cascade and transforming growth factor-beta (TGF-β) activation that were manifested mainly by hepatic stellate cells. Moreover, the induction of induced Tregs and wound healing were both impaired in mice lacking TGF-β signaling or MMPs. The depletion of induced Tregs also impeded wound healing for tissue repair. Together, this study demonstrates the mechanism that the loss of nTregs through apoptosis in the acute phase may facilitate inflammation, while regenerated Tregs through MMP9/13-dependent activation of TGF-β in the healing phase are critical to terminate inflammation and allow for wound healing.

Vitamin D in liver diseases: from mechanisms to clinical trials

Traditionally regarded as a typical vitamin regulating calcium and phosphorus homeostasis, vitamin D is now discovered as a highly versatile molecule with emerging roles in immunity, cancer, infectious diseases, fibrosis, fatty liver diseases, and alcoholic liver diseases. A large body of clinical evidence has demonstrated the prevalence and risks of vitamin D deficiency in various chronic diseases. Biologically active vitamin D, 1,25-dihydroxylvitamin D3, is synthesized in two distinct systems. In addition to the classic two-step hydroxylation in the liver and kidneys, 1,25-dihydroxylvitamin D3 can also be produced locally by immune cells in response to infection. The bioactive vitamin D generated in these two pools apparently functions differently: while the former facilitates calcium adsorption and homeostasis, the latter confers immune regulation. The immune regulatory functions of vitamin D are demonstrated by induction of antimicrobial peptides, suppression of innate immune response, induction of Th2 cytokines, and stimulation of T-regulatory T cells. Vitamin D deficiency or insufficiency is overwhelmingly associated with viral hepatitis, cirrhosis, and fatty liver diseases. Recent clinical trials have shown that vitamin D supplements significantly enhance the efficacy of interferon plus ribavirin therapy through sustained virological response. A recent study showed that 25-dihydroxyvitamin D rather than 1,25-dihydroxyvitamin D could directly suppress hepatitis C virus assembly. Moreover, clinical evidence has shown that vitamin D deficiency is associated with alcoholic and non-alcoholic fatty liver diseases. In this review, we highlight some recent advances in vitamin D researches and clinical trails.

Interleukin-1 as an injury signal mobilizes retinyl esters in hepatic stellate cells through down regulation of lecithin retinol acyltransferase

Retinoids are mostly stored as retinyl esters in hepatic stellate cells (HSCs) through esterification of retinol and fatty acid, catalyzed by lecithin-retinol acyltransferase (LRAT). This study is designated to address how retinyl esters are mobilized in liver injury for tissue repair and wound healing. Initially, we speculated that acute inflammatory cytokines may act as injury signal to mobilize retinyl esters by down-regulation of LRAT in HSCs. By examining a panel of cytokines we found interleukin-1 (IL-1) can potently down-regulate mRNA and protein levels of LRAT, resulting in mobilization of retinyl esters in primary rat HSCs. To simulate the microenvironment in the space of Disse, HSCs were embedded in three-dimensional extracellular matrix, by which HSCs retaine quiescent phenotypes, indicated by up-regulation of LRAT and accumulation of lipid droplets. Upon IL-1 stimulation, LRAT expression went down together with mobilization of lipid droplets. Secreted factors from Kupffer cells were able to suppress LRAT expression in HSCs, which was neutralized by IL-1 receptor antagonist. To explore the underlying mechanism we noted that the stability of LRAT protein is not significantly regulated by IL-1, indicating the regulation is likely at transcriptional level. Indeed, we found that IL-1 failed to down-regulate recombinant LRAT protein expressed in HSCs by adenovirus, while transcription of endogenous LRAT was promptly decreased. Following liver damage, IL-1 was promptly elevated in a close pace with down-regulation of LRAT transcription, implying their causative relationship. After administration of IL-1, retinyl ester levels in the liver, as measured by LC/MS/MS, decreased in association with down-regulation of LRAT. Likewise, IL-1 receptor knockout mice were protected from injury-induced down-regulation of LRAT. In summary, we identified IL-1 as an injury signal to mobilize retinyl ester in HSCs through down-regulation of LRAT, implying a mechanism governing transition from hepatic injury to wound healing.

Therapeutic window, a critical developmental stage for stem cell therapies

In children, cancers are the deadliest of diseases and second only to accidents as the leading cause of death. The deadliest of the brain cancers are the malignant gliomas. Approximately two-thirds of children can survive less malignant types of brain cancers, however, in ~67% of these survivors recurs under the current regimes of surgery followed by administration of high doses toxic drugs and exposure to high doses of radiation. Even more distressing is that fortunate survivors are generally left with life-long cognitive disabilities. A new medical approach is desperately needed. Stem cells, with their natural ability to seek out brain tumors, could be used to accurately deliver therapy directly to the cancer sparing normal tissues for suppression of tumor growth. Despite exciting initial reports, clinical potency of stem cell therapy in animal brain tumor models has to date proven disappointing. Attempts to extrapolate the animal study results to humans are stymied by the fact that stem cells are heterogeneous, resulting in differences in their efficacy. Indeed, therapeutic success relies on an effective strategy to select for a stem cell sub-population within some particular stage of the development at which they are competitive and capable of targeting brain tumors. To improve this during developmental path, concept of a 'therapeutic window' is proposed. The "therapeutic window" for stem cells or more specifically a "biochemical therapeutic window" can be determined from biochemical assays and a "biological therapeutic window" from biological assays or even a molecular window for genetic description. Taken together, we can use selective processes to generate more effective stem cells to treat cancers as is clearly needed today.

Study of scattering from a sphere with an eccentrically located spherical inclusion by generalized Lorenz-Mie theory: internal and external field distribution

Based on the recent results in the generalized Lorenz-Mie theory, solutions for scattering problems of a sphere with an eccentrically located spherical inclusion illuminated by an arbitrary shaped electromagnetic beam in an arbitrary orientation are obtained. Particular attention is paid to the description and application of an arbitrary shaped beam in an arbitrary orientation to the scattering problem under study. The theoretical formalism is implemented in a homemade computer program written in FORTRAN. Numerical results concerning spatial distributions of both internal and external fields are displayed in different formats in order to properly display exemplifying results. More specifically, as an example, we consider the case of a focused fundamental Gaussian beam (TEM(00) mode) illuminating a glass sphere (having a real refractive index equal to 1.50) with an eccentrically located spherical water inclusion (having a real refractive index equal to 1.33). Displayed results are for various parameters of the incident electromagnetic beam (incident orientation, beam waist radius, location of the beam waist center) and of the scatterer system (location of the inclusion inside the host sphere and relative diameter of the inclusion to the host sphere).

Epigenetic repression of matrix metalloproteinases in myofibroblastic hepatic stellate cells through histone deacetylases 4: implication in tissue fibrosis

Matrix metalloproteinases (MMPs), which are highly expressed in acute injury, are progressively repressed or silenced in fibrotic liver, favoring extracellular matrix accumulation, while the underlying mechanism is largely unknown. Similarly, normal/quiescent hepatic stellate cells (HSCs) express high levels of MMPs in response to injury signals, such as interleukin-1. After transdifferentiation, the myofibroblastic HSCs are incapable of expressing many MMPs; however, the major signaling pathways required for MMP expression are intact, indicating that repression is at the level of the chromatin. Indeed, both the MMP9 and MMP13 genes are inaccessible to transcription factors and RNA polymerase II, in association with impaired histone acetylation in their promoters. In accordance with impaired histone acetylation at the cellular level, histone deacetylase-4 is accumulated during HSC transdifferentiation. Furthermore, ectopic expression of histone deacetylase-4 in quiescent HSCs results in repression of MMP promoter activities as well as endogenous MMP9 protein expression. Thus, our findings suggest that a histone deacetylase-4-dependent mechanism underlies the epigenetic silencing of MMP genes during tissue fibrogenesis.

c-Jun mediates hepatitis C virus hepatocarcinogenesis through signal transducer and activator of transcription 3 and nitric oxide-dependent impairment of oxidative DNA repair

Hepatocellular carcinoma (HCC) occurs in a significant number of patients with hepatitis C virus (HCV) infection. HCV causes double-strand DNA breaks and enhances the mutation frequency of proto-oncogenes and tumor suppressors. However, the underlying mechanisms for these oncogenic events are still elusive. Here, we studied the role of c-Jun, signal transducer and activator of transcription 3 (STAT3), and nitric oxide (NO) in spontaneous and diethylnitrosamine (DEN)-initiated and/or phenobarbital (Pb)-promoted HCC development using HCV core transgenic (Tg) mice. The viral core protein induces hepatocarcinogenesis induction as a tumor initiator under promotion by Pb treatment alone. Conditional knockout of c-jun and stat3 in hepatocytes achieves a nearly complete, additive effect on prevention of core-induced spontaneous HCC or core-enhanced HCC incidence caused by DEN/Pb. Core protein induces hepatocyte proliferation and the expression of inflammatory cytokines (interleukin-6, tumor necrosis factor-alpha, interleukin-1) and inducible NO synthase (iNOS); the former is dependent on c-Jun and STAT3, and the latter on c-Jun. Oxidative DNA damage repair activity is impaired by the HCV core protein due to reduced DNA glycosylase activity for the excision of 8-oxo-2'-deoxyguanosine. This impairment is abrogated by iNOS inhibition or c-Jun deficiency, but aggravated by the NO donor or iNOS-inducing cytokines. The core protein also suppresses apoptosis mediated by Fas ligand because of c-Jun-dependent Fas down-regulation.

CONCLUSION

These results indicate that the HCV core protein potentiates chemically induced HCC through c-Jun and STAT3 activation, which in turn, enhances cell proliferation, suppresses apoptosis, and impairs oxidative DNA damage repair, leading to hepatocellular transformation.

Epithelial to mesenchymal transition in human skin wound healing is induced by tumor necrosis factor-alpha through bone morphogenic protein-2

Epithelial-mesenchymal transition (EMT), characterized by loss of epithelial adhesion and gain of mesenchymal features, is an important mechanism to empower epithelial cells into the motility that occurs during embryonic development and recurs in cancer and fibrosis. Whether and how EMT occurs in wound healing and fibrosis in human skin remains unknown. In this study we found that migrating epithelial cells in wound margins and deep epithelial ridges had gained mesenchymal features such as vimentin and FSP1 expression. In hypertrophic scars, EMT-related genes were elevated along with inflammatory cytokines, indicating a causal relationship. To reconstitute EMT in vitro, normal human skin and primary keratinocytes were exposed to cytokines such as tumor necrosis factor-alpha (TNF-alpha), resulting in expression of vimentin, FSP1, and matrix metalloproteinases. Moreover, TNF-alpha-induced EMT was impaired by antagonists against bone morphogen proteins (BMP) 2/4, suggesting that BMP mediates the TNF-alpha-induced EMT in human skin. Indeed, TNF-alpha could induce BMP-2 and its receptor (BMPR1A) in human skin and primary keratinocytes, and BMP2 could induce EMT features in skin explants and primary keratinocytes. In summary, we uncovered EMT features in both acute and fibrotic cutaneous wound healing of human skin. Moreover, we propose that the mesenchymal induction in wound healing is motivated by TNF-alpha, in part, through induction of BMP.

Alpha1-antichymotrypsin activity correlates with and may modulate matrix metalloproteinase-9 in human acute wounds

Matrix metalloproteinase-9 (MMP-9) plays a central role in many physiologic processes including acute and the chronic wounds. MMP-9 is not routinely expressed in healthy tissues but is promptly expressed as a proenzyme and converted into active enzyme after tissue injury. The mechanisms involved, including the activators and inhibitors for this enzyme in human tissue remain largely obscure. We recently identified alpha1-antichymotrypsin (alpha1-ACT), an acute phase factor, as a potent inhibitor controlling activation of pro-MMP-9 by human skin. The aim of this study is to establish the clinical relevance of the inhibitor in cutaneous wound healing. Fluids from acute burn blisters and conditioned media from skin explants of burn patients were analyzed. We observed that the presence pro-MMP-9 and its activation correlated with the proximity to and degree of injury. Early after trauma, massive levels of wound alpha1-ACT were associated with an absence of pro-MMP-9 activation. Conversely, the active MMP-9 occurs simultaneously with inactivation of alpha1-ACT. Our results suggest a role for alpha1-ACT as a physiologic inhibitor of MMP-9 activation in human wound healing.

DNA mismatch repair related gene expression as potential biomarkers to assess cadmium exposure in Arabidopsis seedlings

In the current study, Arabidopsis seedlings were hydroponically grown on MS media containing cadmium (Cd) of 0-2.0 mg L(-1) for 60 h of treatment. Gene expression profiles were used to relate exposure to Cd with some altered biological responses and/or specific growth effects. RT-PCR analysis was used to quantitate mRNA expression for seven genes known to be involved in DNA mismatch repair (MMR) system and cell division. Results indicated that Cd concentrations of 0.25-2.0 mg L(-1) cause increased total soluble protein levels in shoots of Arabidopsis seedlings in an inverted U-shaped dose-response manner. Exposure to 0.25 and 0.5 mg L(-1) of Cd dramatically induced expression of four genes (i.e. proliferating cell nuclear antigen 2 (atPCNA 2), MutL1 homolog (atMLH1), MutS 2 homolog (atMSH2) and atMSH3) and five genes (i.e. atPCNA1,2, atMLH1 and atMSH2,7), respectively, in shoots of Arabidopsis seedlings; Exposure to 1.0 mg L(-1) of Cd significantly elevated expression of only two genes (atMSH6,7), but caused prominent inhibition in expression of three genes (atPCNA2, atMLH1 and atMSH3) in shoots of Arabidopsis seedlings. The expression alterations of the above genes were independent of any biological effects such as survival, fresh weight and chlorophyll level of shoots. However, shoots of Arabidopsis seedlings exposed to 2.0 mg L(-1) of Cd exhibited statistically prominent repression in expression of these seven genes, and showed incipient reduction of fresh weight and chlorophyll level. This research provides data concerning sensitivity of expression profiles of atMLH1, atMSH2,3,6,7 and atPCNA1,2 genes in Arabidopsis seedlings to Cd exposure, as well as the potential use of these gene expression patterns as representative molecular biomarkers indicative of Cd exposure and related biological effects.

Interleukin-1 participates in the progression from liver injury to fibrosis

Interleukin-1 (IL-1) is rapidly expressed in response to tissue damage; however, its role in coordinating the progression from injury to fibrogenesis is not fully understood. Liver fibrosis is a consequence of the activation of hepatic stellate cells (HSCs), which reside within the extracellular matrix (ECM) of subsinusoids. We have hypothesized that, among the hepatic inflammatory cytokines, IL-1 may directly activate HSCs through autocrine signaling and stimulate the matrix metalloproteinases (MMPs) produced by HSCs within the space of Disse, resulting in liver fibrogenesis. In this study, we first established a temporal relationship between IL-1, MMPs, HSC activation, and early fibrosis. The roles of IL-1 and MMP-9 in HSC activation and fibrogenesis were determined by mice deficient of these genes. After liver injury, IL-1, MMP-9, and MMP-13 levels were found to be elevated before the onset of HSC activation and fibrogenesis. IL-1 receptor-deficient mice exhibited ameliorated liver damage and reduced fibrogenesis. Similarly, advanced fibrosis, as determined by type-I and -III collagen mRNA expression and fibrotic septa, was partially attenuated by the deficiency of IL-1. In the early phase of liver injury, the MMP-9, MMP-13, and TIMP-1 expression correlated well with IL-1 levels. In injured livers, MMP-9 was predominantly colocalized to desmin-positive cells, suggesting that HSCs are MMP-producing cells in vivo. MMP-9-deficient mice were partially protected from liver injury and HSC activation. Thus IL-1 is an important participant, along with other cytokines, and controls the progression from liver injury to fibrogenesis through activation of HSCs in vivo.

Interleukin-1 participates in the progression from liver injury to fibrosis

Interleukin-1 (IL-1) is rapidly expressed in response to tissue damage; however, its role in coordinating the progression from injury to fibrogenesis is not fully understood. Liver fibrosis is a consequence of the activation of hepatic stellate cells (HSCs), which reside within the extracellular matrix (ECM) of subsinusoids. We have hypothesized that, among the hepatic inflammatory cytokines, IL-1 may directly activate HSCs through autocrine signaling and stimulate the matrix metalloproteinases (MMPs) produced by HSCs within the space of Disse, resulting in liver fibrogenesis. In this study, we first established a temporal relationship between IL-1, MMPs, HSC activation, and early fibrosis. The roles of IL-1 and MMP-9 in HSC activation and fibrogenesis were determined by mice deficient of these genes. After liver injury, IL-1, MMP-9, and MMP-13 levels were found to be elevated before the onset of HSC activation and fibrogenesis. IL-1 receptor-deficient mice exhibited ameliorated liver damage and reduced fibrogenesis. Similarly, advanced fibrosis, as determined by type-I and -III collagen mRNA expression and fibrotic septa, was partially attenuated by the deficiency of IL-1. In the early phase of liver injury, the MMP-9, MMP-13, and TIMP-1 expression correlated well with IL-1 levels. In injured livers, MMP-9 was predominantly colocalized to desmin-positive cells, suggesting that HSCs are MMP-producing cells in vivo. MMP-9-deficient mice were partially protected from liver injury and HSC activation. Thus IL-1 is an important participant, along with other cytokines, and controls the progression from liver injury to fibrogenesis through activation of HSCs in vivo.

Tumor necrosis factor-alpha induced expression of matrix metalloproteinase-9 through p21-activated kinase-1

Background

Expressed in embryonic development, matrix metalloprotein-9 (MMP-9) is absent in most of developed adult tissues, but recurs in inflammation during tissue injury, wound healing, tumor formation and metastasis. Expression of MMP-9 is tightly controlled by extracellular cues including pro-inflammatory cytokines and extracellular matrix (ECM). While the pathologic functions of MMP-9 are evident, the intracellular signaling pathways to control its expression are not fully understood. In this study we investigated mechanism of cytokine induced MMP-9 with particular emphasis on the role of p21-activated-kinase-1 (PAK1) and the down stream signaling.

Results

In response to TNF-alpha or IL-1alpha, PAK1 was promptly activated, as characterized by a sequential phosphorylation, initiated at threonine-212 followed by at threonine-423 in the activation loop of the kinase, in human skin keratinocytes, dermal fibroblasts, and rat hepatic stellate cells. Ectopic expression of PAK1 variants, but not p38 MAP kinase, impaired the TNF-alpha-induced MMP-9 expression, while other MMPs such as MMP-2, -3 and -14 were not affected. Activation of Jun N-terminal kinase (JNK) and NF-kappaB has been demonstrated to be essential for MMP-9 expression. Expression of inactive PAK1 variants impaired JNK but not NF-kappaB activation, which consequently suppressed the 5'-promoter activities of the MMP-9 gene. After the cytokine-induced phosphorylation, both ectopically expressed and endogenous PAK1 proteins were promptly accumulated even in the condition of suppressing protein synthesis, suggesting the PAK1 protein is stabilized upon TNF-alpha stimulation. Stabilization of PAK1 protein by TNF-alpha treatment is independent of the kinase catalytic activity and p21 GTPase binding capacities. In contrast to epithelial cells, mesenchymal cells require 3-dimensional type-I collagen in response to TNF-alpha to massively express MMP-9. The collagen effect is mediated, in part, by boost JNK activation in a way to cooperate the cytokine signaling.

Conclusion

We identified a novel mechanism for MMP-9 expression in response to injury signals, which is mediated by PAK1 activation and stabilization leading JNK activation.

Risk assessment of cadmium-contaminated soil on plant DNA damage using RAPD and physiological indices

Impact assessment of contaminants in soil is an important issue in environmental quality study and remediation of contaminated land. A random amplified polymorphic DNA (RAPD) 'fingerprinting' technique was exhibited to detect genotoxin-induced DNA damage of plants from heavy metal contaminated soil. This study compared the effects occurring at molecular and population levels in barley seedlings exposed to cadmium (Cd) contamination in soil. Results indicate that reduction of root growth and increase of total soluble protein level in the root tips of barley seedlings occurred with the ascending Cd concentrations. For the RAPD analyses, nine 10-base pair (bp) random RAPD primers (decamers) with 60-70% GC content were found to produce unique polymorphic band patterns and subsequently were used to produce a total of 129 RAPD fragments of 144-2639 base pair in molecular size in the root tips of control seedlings. Results produced from nine primers indicate that the changes occurring in RAPD profiles of the root tips following Cd treatment included alterations in band intensity as well as gain or loss of bands compared with the control seedlings. New amplified fragments at molecular size from approximately 154 to 2245 bp appeared almost for 10, 20 and 40 mg L(-1) Cd with 9 primers (one-four new polymerase chain reaction, (PCR) products), and the number of missing bands enhanced with the increasing Cd concentration for nine primers. These results suggest that genomic template stability reflecting changes in RAPD profiles were significantly affected and it compared favourably with the traditional indices such as growth and soluble protein level at the above Cd concentrations. The DNA polymorphisms detected by RAPD can be applied as a suitable biomarker assay for detection of the genotoxic effects of Cd stress in soil on plants. As a tool in risk assessment the RAPD assay can be used in characterisation of Cd hazard in soil.

Contribution of hepatic stellate cells and matrix metalloproteinase 9 in acute liver failure

BACKGROUND/AIMS

Fulminant hepatitis or acute liver failure (ALF), initiated by viral infection or hepatic toxin, is a devastating medical complication without effective therapeutic treatment. In this study, we addressed the potential roles of hepatic stellate cells (HSCs) and their produced matrix metalloproteinases (MMPs) in development of ALF.

METHODS

Mice were given lipopolysaccharide (LPS) and beta-galactosamine (GA) or carbon tetrachloride to create ALF and establish the association of IL-1, MMP-9, and caspase-3 in acute liver failure.

RESULTS

In response to the hepatic toxin, IL-1 and MMP-9 were promptly induced within 1 hour, followed by caspase-3 activation at 2 hours, and dehiscence of sinusoids at 4 hours, and consequent lethality. In contrast, MMP-9 knockout mice were resistant to lethality and absent of caspase-3 activation, demonstrating an MMP-9-dependent activation of caspase in vivo. Further, IL-1-receptor knockout mice were resistant to lethality in MMP-9 dependent manner, indicating a causative relationship. Although many hepatic cells are capable to produce MMP-9 in vitro, HSCs were demonstrated here as the major hepatic cells to express MMP-9 in liver injury. To recapitulate the sinusoidal microenvironment we cultured primary HSCs in 3-dimensional ECM. In response to IL-1, massive MMP-9 was produced by the 3D culture concomitantly with degradation of type-IV collagen.

CONCLUSIONS

Based on these evidences, we propose a novel model to highlight the initiation of acute liver failure: IL-1-induced MMPs by HSCs within the space of Disse and thereafter ECM degradation may provoke the collapse of sinusoids, leading parenchymal cell death and loss of liver functions.

Wnt antagonism inhibits hepatic stellate cell activation and liver fibrosis

Activation of hepatic stellate cells (HSC), a key event in liver fibrosis, is caused by diminished adipogenic transcription. This study investigated whether Wnt signaling contributes to "antiadipogenic" activation of HSC and liver fibrogenesis. Culture-activated HSC from normal rats and HSC from cholestatic rat livers were examined for expression of Wnt, Frizzled (Fz) receptors, and coreceptors by quantitative PCR. Wnt signaling was assessed by nuclear beta-catenin and T cell factor (TCF) promoter activity. Dickkopf-1 (Dkk-1), a Wnt coreceptor antagonist, was transduced by an adenoviral vector to assess the effects of Wnt antagonism on culture activation of HSC and cholestatic liver fibrosis in mice. Messenger RNA for canonical (Wnt3a and 10b) and noncanonical (Wnt4 and 5a) Wnt genes, Fz-1 and 2, and coreceptors [low-density lipoprotein-receptor-related protein (LRP)6 and Ryk] are increased approximately 3-12-fold in culture-activated HSC compared with quiescent HSC. The nuclear beta-catenin level and TCF DNA binding are markedly increased in activated HSC. TCF promoter activity is stimulated with Wnt1 but inhibited by Chibby, a protein that blocks beta-catenin interaction with TCF, and by Dkk-1. Dkk-1 enhances peroxisome proliferator-activated receptor-gamma (PPARgamma)-driven PPAR response element (PPRE) promoter activity, a key adipogenic transcriptional parameter, abrogates agonist-stimulated contraction, and restores HSC quiescence in culture. High expression of Dkk-1 increases apoptosis of cultured HSC. Expression of Wnt and Fz genes is also induced in HSC isolated from experimental cholestatic liver fibrosis, and Dkk-1 expression ameliorates this form of liver fibrosis in mice. These results demonstrate antiadipogenic Wnt signaling in HSC activation and therapeutic potential of Wnt antagonism for liver fibrosis.