Possible role of REG Ialpha protein in ulcerative colitis and colitic cancer

REG1A protects retinal photoreceptors from blue light damage

With the increased use of artificial light and the prolonged use of optoelectronic products, light damage (LD) to the human retina has been identified as a global vision-threatening problem. While there is evidence of a significant correlation between light-induced retinal damage and age-related vision impairment in age-related macular degeneration, it is unclear how light-induced retinal degeneration manifests itself and whether there are agents capable of preventing the development of LD in the retina. This study investigated a mechanism by which blue light leads to photoreceptor death. By observing blue light exposure in retinal organoids and photoreceptor cells, we concluded that there could be significant apoptosis of the photoreceptors. We demonstrate that regenerating islet-derived 1 alpha (REG1A) prevents photoreceptors from undergoing this LD-induced apoptosis by increasing expression of the anti-apoptotic gene Bcl2 and downregulating expression of the pro-apoptotic gene Bax, resulting in reduced mitochondrial damage and improved aerobic capacity in photoreceptor cells. For the first time, REG1A has been shown to restore mitochondrial function and cell apoptosis after LD-induced damage, suggesting its potential application in the prevention and treatment of retinal vision loss.

Identification of diagnostic signatures in ulcerative colitis patients via bioinformatic analysis integrated with machine learning

Ulcerative colitis (UC) is an immune-related disorder with enhanced prevalence globally. Early diagnosis is critical for the effective treatment of UC. However, it still lacks specific diagnostic signatures. The aim of our study was to explore efficient signatures and construct the diagnostic model for UC. Microarray data of GSE87473 and GSE48634, which were obtained from tissue biopsy samples, were downloaded from the Gene Expression Omnibus (GEO), and differently expressed genes (DEGs), GO, and KEGG analyses were performed. We constructed the PPI network via STRING database. The immune infiltration of the samples was evaluated using CIBERSORT methods combined with the LM22 feature matrix. The logistic regression model was constructed, with the expression of selected genes as the predictor variable, and the UC occurrence as the responsive variable. As a result, a total of 126 DEGs between the UC patients and normal counterparts were identified. The GO and KEGG analysis revealed that multiple biological processes, such as antimicrobial humoral immune response mediated by antimicrobial peptide and IL-17 signaling pathway, were enriched. The infiltration of eight immune cell types (B cells naive, Dendritic.cells.activated, Macrophages.M0, Macrophages.M2, Mast.cells.resting, Neutrophils, Plasma.cells, and T.cells.follicular.helper) was significantly different between patients with UC and normal counterparts. The top 50 most significant DEGs were selected for the construction of the PPI network. The average AUC of the logistic regression model in the fivefold cross-validation was 0.8497 in the training set, GSE87473. The AUC of another independent verification set of GSE48634 from the GEO database was 0.7208. In conclusion, we identified potential hub genes, including REG3A, REG1A, DEFA6, REG1B, and DEFA5, which might be significantly associated with UC progression. The logistic regression model based on the five genes could reliably diagnose UC patients.

The Potential Role of REG Family Proteins in Inflammatory and Inflammation-Associated Diseases of the Gastrointestinal Tract

Regenerating gene (REG) family proteins serve as multifunctional secretory molecules with trophic, antiapoptotic, anti-inflammatory, antimicrobial and probably immuno-regulatory effects. Since their discovery, accumulating evidence has clarified the potential roles of the REG family in the occurrence, progression and development of a wide range of inflammatory and inflammation-associated diseases of the gastrointestinal (GI) tract. However, significant gaps still exist due to the undefined nature of certain receptors, regulatory signaling pathways and possible interactions among distinct Reg members. In this narrative review, we first describe the structural features, distribution pattern and purported regulatory mechanisms of REG family proteins. Furthermore, we summarize the established and proposed roles of REG proteins in the pathogenesis of various inflammation-associated pathologies of the GI tract and the body as a whole, focusing particularly on carcinogenesis in the ulcerative colitis—colitic cancer sequence and gastric cancer. Finally, the clinical relevance of REG products in the context of diagnosis, treatment and prognostication are also discussed in detail. The current evidence suggests a need to better understanding the versatile roles of Reg family proteins in the pathogenesis of inflammatory-associated diseases, and their broadened future usage as therapeutic targets and prognostic biomarkers is anticipated.

Whole genome transcriptome analysis of the stomach resected in human vertical sleeve gastrectomy: cutting more than calories

Vertical sleeve gastrectomy (VSG) is a surgical weight loss procedure that resects 80% of the stomach, creating a tube linking the esophagus to the duodenum. Because of the efficacy and relative simplicity of VSG, it is preferred in the United States, with VSG currently at >61% of bariatric surgeries performed. Surprisingly, there has never been a complete molecular characterization of the human stomach greater curvature's fundus and corpus. Here we compare and contrast the molecular makeup of these regions. We performed a prospective cohort study to obtain gastric tissue samples from patients undergoing elective VSG. Paired fundus and corpus samples were obtained. Whole genome transcriptome analysis was performed by RNA sequencing (N = 10), with key findings validated by qPCR (N = 24). Participants were primarily female (95.8%) and White (79.15%). Mean body mass index, body weight, and age were 46.1 kg/m², 121.6 kg, and 43.29 yr, respectively. Overall, 432 gene transcripts were significantly different between the fundus and the corpus (P < 0.05). A significant correlation was found between the RNA sequencing dataset and qPCR validation, demonstrating robust gene expression differences between the fundus and the corpus. Significant genes included progastricsin, acidic chitinase, and gastokine 1 and 2 in both the fundus and the corpus. Of the very highly expressed genes in both regions, 87% were present in both the stomach's fundus and corpus, indicating substantial overlap. Despite significant overlap in the greater curvature gene signature, regional differences exist within the fundus and the corpus. Given that the mechanism of VSG is partly unresolved, the potential that the resected tissue may express genes that influence long-term body weight regulation is unknown and could influence VSG outcomes.

Role of the β-Catenin/REG Iα Axis in the Proliferation of Sessile Serrated Adenoma/Polyps Associated with Fusobacterium nucleatum

Although sessile serrated adenoma/polyps (SSA/Ps) may arise through a pathway different from the traditional adenoma–carcinoma sequence, details of SSA/P tumorigenesis still remain unclear. Fusobacterium nucleatum (Fn) is frequently detected in colorectal cancer (CRC) tissues and may play a pivotal role in colorectal carcinogenesis. Here, we investigated the relationship between Fn and the β-catenin/REG Iα axis in SSA/Ps and their involvement in the proliferation of these lesions. Fn was detected in SSA/Ps by fluorescence in situ hybridization using a Fn-targeted probe, and expression of β-catenin, REG Iα and Ki67 was examined using immunohistochemistry. Sixteen of 30 SSA/P lesions (53.3%) were positive for Fn. Eighteen SSA/P lesions (60%) showed β-catenin immunoreactivity in the tumor cell nuclei. A significant majority of Fn-positive lesions showed nuclear expression of β-catenin (87.5%) and higher REG Iα scores and Ki67 labeling indices relative to Fn-negative lesions. The SSA/P lesions expressing β-catenin in nuclei had significantly higher REG Iα scores and Ki67 labeling indices than those expressing β-catenin on cytomembranes. The REG Iα score was positively correlated with the Ki67 labeling index in SSA/P lesions. The treatment with Wnt agonist SKL2001 promoted nuclear β-catenin translocation and enhanced REG Ia expression in Caco2 cells. Fn may play a role in the proliferation of SSA/P lesions through promotion of β-catenin nuclear translocation and REG Iα expression.

Protective and anti-inflammatory role of REG1A in inflammatory bowel disease induced by JAK/STAT3 signaling axis

Regenerating islet-derived protein 1-alpha (REG1A) was abnormally upregulated in a series of gastrointestinal inflammatory disorders. However, the potential biological function and underlying regulatory mechanisms of the increased REG1A in inflammatory bowel disease (IBD) pathogenesis remain to be fully elucidated. In this study, we uncovered that REG1A was substantially increased in the inflamed colorectal tissues of IBD patients. And the aberrantly expressed REG1A in intestinal epithelial cells (IEC) prominently inhibited inflammatory responses, promoted cell proliferation and suppressed epithelial apoptosis. Mechanically, IL-6 and IL-22 markedly activated REG1A transcription through triggering JAK/STAT3 signaling pathway. In addition, overexpression of REG1A in mice by systematic delivery of REG1A lentivirus remarkably alleviated DSS-induced inflammatory injury and maintained the integrity of intestinal mucosal barrier. Taken together, our data demonstrated that the novel proliferative factor REG1A controlled by IL-6/IL-22-JAK-STAT3 signaling may provide a promising therapeutic target for patients with IBD.

Carboxypeptidase A1 and regenerating islet-derived 1α as new markers for pancreatic acinar cell carcinoma

Acinar cell carcinoma (ACC) is a rare tumor that differentiates toward pancreatic acinar cells and shows evidence of pancreatic enzyme production. Mixed acinar-neuroendocrine carcinoma (MANC) is defined as having more than 30% of both acinar and neuroendocrine cell types as per immunohistochemistry analysis. Trypsin is currently the most commonly used stain for acinar differentiation. In this study, we investigate the utility of two novel markers, carboxypeptidase A1 (CPA1) and regenerating islet-derived 1α (REG1a), in diagnosing ACC/MANC. Immunohistochemical staining for CPA1 and REG1a was performed on 14 cases of ACC and 5 cases of MANC as well as on 80 other pancreatic tumors including 20 cases each of ductal adenocarcinoma, well-differentiated neuroendocrine tumor, mucinous cystic neoplasm, and solid pseudopapillary tumor. All ACCs and MANCs were positive for CPA1 (all diffuse) and REG1a (12 diffuse, 4 patchy, and 3 focal). A diffuse or patchy staining pattern was significantly more common in ACC/MANC cases (100% diffuse/patchy for CPA1 and 84% for REG1a) than in other pancreatic tumors (5% diffuse/patchy for CPA1 and 7.5% for REG1a), with a P-value of <0.0001 for both CPA1 and REG1a. The sensitivity and specificity of diffuse/patchy staining for CPA1 and REG1a in diagnosing pancreatic ACC/MANC were 100% and 95% for CPA1 and 84% and 93% for REG1a, respectively. In conclusion, CPA1 and REG1a are sensitive markers for ACC that can be used as additional acinar cell differentiation markers to help in the diagnosis of pancreatic ACC and MANC. A negative result for CPA1 virtually excludes ACC/MANC.

The Link between Type III Reg and STAT3-Associated Cytokines in Inflamed Colonic Tissues

Reg (regenerating gene) family proteins are known to be overexpressed in gastrointestinal (GI) tissues under conditions of inflammation. However, the pathophysiological significance of Reg family protein overexpression and its regulation is still unclear. In the present study, we investigated the profile of Reg family gene expression in a colitis model and focused on the regulation of Reg IIIβ and IIIγ, which are overexpressed in inflamed colonic mucosa. C57BL/6 mice were administered 2% dextran sulfate sodium (DSS) in drinking water for five days, and their colonic tissues were investigated histopathologically at interval for up to 12 weeks. Gene expression of the Reg family and cytokines (IL-6, IL-17, and IL-22) was evaluated by real-time RT-PCR, and Reg IIIβ/γ expression was examined by immunohistochemistry. The effects of cytokines on STAT3 phosphorylation and HIP/PAP (type III REG) expression in Caco2 and HCT116 cells were examined by Western blot analysis. Among Reg family genes, Reg IIIβ and IIIγ were alternatively overexpressed in the colonic tissues of mice with DSS-induced colitis. The expression of STAT3-associated cytokines (IL-6, IL-17, and IL-22) was also significantly increased in those tissues, being significantly correlated with that of Reg IIIβ/γ. STAT3 phosphorylation and HIP/PAP expression were significantly enhanced in Caco2 cells upon stimulation with IL-6, IL-17, and IL-22. In HCT116 cells, those enhancements were also observed by IL-6 and IL-22 stimulations but not IL-17. The link between type III Reg and STAT3-associated cytokines appears to play a pivotal role in the pathophysiology of DSS-induced colitis.

Knockdown of REG Iα Enhances the Sensitivity to 5-Fluorouracil of Colorectal Cancer Cells via Cyclin D1/CDK4 Pathway and BAX/BCL-2 Pathways

Objective: The reverse of chemoresistance and the improvement of sensitivity to chemotherapeutic agents of colorectal cancer cells have great clinical significance and the mechanism underlying the drug resistance is still unclear. REG Iα was reported to be upregulated in colorectal cancer tissues, but the roles of chemoresistance are still unclear. Materials and Methods: The expression of REG Iα in colorectal cancer cell lines was assessed by quantitative real-time polymerase chain reaction (Q-PCR). The expression of REG Iα in HCT116 and LOVO cells was knockdown by siRNA. The cell viability and IC₅₀ (half maximal inhibitory concentration) values were analyzed by the CCK8 assay. The proportion of apoptosis and cell cycles were analyzed by flow cytometry. The migration potency of HCT116 and LOVO cells was analyzed by cell migration assay. The protein level of Cyclin D1, CDK4 (cyclin-dependent kinase 4), Bax and Bcl-2 were analyzed by western blot. Results: Knockdown of REG Iα enhances the sensitivity to 5-Fu of colorectal cancer cells. REG Iα knockdown promoted the cell apoptosis of HCT116 and LOVO under the 5-Fu treatment. The cell migration and cycle of colorectal cancer cells was also inhibited by REG Iα knockdown. We also found that REG Iα knockdown induced cell cycle arrest and cell apoptosis by Cyclin D1/CDK4 pathway and BAX/BCL-2 pathways. Conclusions: Knockdown of REG Iα enhances the sensitivity to 5-Fu of colorectal cancer cells via cyclin D1/CDK4 pathway and BAX/BCL-2 pathways.

Deficiency in intestinal epithelial Reg4 ameliorates intestinal inflammation and alters the colonic bacterial composition

The regenerating islet-derived family member 4 (Reg4) in the gastrointestinal tract is up-regulated during intestinal inflammation. However, the physiological function of Reg4 in the inflammation is largely unknown. In the current study, the functional roles and involved mechanisms of intestinal epithelial Reg4 in intestinal inflammation were studied in healthy and inflamed states using human intestinal specimens, an intestinal conditional Reg4 knockout mouse (Reg4^ΔIEC) model and dextran sulfate sodium (DSS)-induced colitis model. We showed that the elevated serum Reg4 in pediatric intestinal failure (IF) patients were positively correlated with the serum concentrations of proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). In inflamed intestine of IF patients, the crypt base Reg4 protein was increased and highly expressed towards the luminal face. The Reg4 was indicated as a novel target of activating transcription factor 2 (ATF2) that enhanced Reg4 expression during the intestinal inflammation. In vivo, the DSS-induced colitis was significantly ameliorated in Reg4^ΔIEC mice. Reg4^ΔIEC mice altered the colonic bacterial composition and reduced the bacteria adhere to the colonic epithelium. In vitro, Reg4 was showed to promote the growth of colonic organoids, and that this occurs through a mechanism involving activation of signal transducer and activator of transcription 3 (STAT3). In conclusion, our findings demonstrated intestinal-epithelial Reg4 deficiency protects against experimental colitis and mucosal injury via a mechanism involving alteration of bacterial homeostasis and STAT3 activation.

Significance of Interleukin-6/STAT Pathway for the Gene Expression of REG Iα, a New Autoantigen in Sjögren's Syndrome Patients, in Salivary Duct Epithelial Cells

The regenerating gene, Reg, was originally isolated from a rat regenerating islet complementary DNA (cDNA) library, and its human homologue was named REG Iα. Recently, we reported that REG Iα messenger RNA (mRNA), as well as its product, was overexpressed in ductal epithelial cells in the salivary glands of Sjögren's syndrome patients. Furthermore, autoantibodies against REG Iα were found in the sera of Sjögren's syndrome patients, and the patients who were positive for the anti-REG Iα antibody showed significantly lower saliva secretion than antibody-negative patients. We found the mechanism of REG Iα induction in salivary ductal epithelial cells. Reporter plasmid containing REG Iα promoter (-1190/+26) upstream of a luciferase gene was introduced into human NS-SV-DC and rat A5 salivary ductal cells. The cells were treated with several cytokines (interleukin (IL)-6, IL-8, etc.), upregulated in Sjögren's syndrome salivary ducts, and the transcriptional activity was measured. IL-6 stimulation significantly enhanced the REG Iα promoter activity in both cells. Deletion analysis revealed that the -141∼-117 region of the REG Iα gene was responsible for the promoter activation by IL-6, which contains a consensus sequence for signal transducer and activator of transcription (STAT) binding. The introduction of small interfering RNA for human STAT3 abolished IL-6-induced REG Iα transcription. These results indicated that IL-6 stimulation induced REG Iα transcription through STAT3 activation and binding to the REG Iα promoter in salivary ductal cells. This dependence of REG Iα induction upon IL-6/STAT in salivary duct epithelial cells may play an important role in the pathogenesis/progression of Sjögren's syndrome.

Promising Biomarkers of Environmental Enteric Dysfunction: A Prospective Cohort study in Pakistani Children

Environmental Enteric Dysfunction (EED), a syndrome characterized by chronic gut inflammation, contributes towards stunting and poor response to enteric vaccines in children in developing countries. In this study, we evaluated major putative biomarkers of EED using growth faltering as its clinical proxy. Newborns (n = 380) were enrolled and followed till 18 months with monthly anthropometry. Biomarkers associated with gut and systemic inflammation were assessed at 6 and 9 months. Linear mixed effects model was used to determine the associations of these biomarkers with growth faltering between birth and 18 months. Fecal myeloperoxidase (neutrophil activation marker) at 6 months [β = −0.207, p = 0.005], and serum GLP 2 (enterocyte proliferation marker) at 6 and 9 months [6M: β = −0.271, p = 0.035; 9M: β = −0.267, p = 0.045] were associated with decreasing LAZ score. Ferritin at 6 and 9 months was associated with decreasing LAZ score [6M: β = −0.882, p < 0.0001; 9M: β = −0.714, p < 0.0001] and so was CRP [β = −0.451, p = 0.039] and AGP [β = −0.443, p = 0.012] at 9 months. Both gut specific and systemic biomarkers correlated negatively with IGF-1, but only weakly correlated, if at all with each other. We therefore conclude that EED may be contributing directly towards growth faltering, and this pathway is not entirely through the pathway of systemic inflammation.

Role of regenerating gene IA expression on local invasion and survival in nasopharyngeal carcinoma

BACKGROUND

Regenerating gene IA (REGIA) plays an important role in tissue regeneration and tumors prognosis of epithelium origin. However, the role of REGIA in nasopharyngeal carcinoma (NPC) is unclear. This study aims to investigate the expression and function of REG1A in NPC.

RESULTS

We have found that there was 63 patients with REGIA positive expression of 155 patients in this study (40.65%). The positive expression rate of REGIA was 30.50, 44.44 and 47.83% in stage T2, T3 and T4 patients, respectively. The REGIA expression was significantly difference in T2 and T4 stage tumors or T2 and T3-T4 stage. The positive expression rate of REGIA was found to be higher in patients with cervical lymph node persistence than those with cervical lymph node complete regression. Patients with negative REGIA expression had a better overall survival and free survival than those with REGIA positive expression. In addition, according to the univariate and multivariate analysis, the REGIA expression was an independent adverse prognostic factor for NPC patients.

CONCLUSION

REGIA expression was a useful biomarker in NPC patients for assessing T stage and survival.

Environmental Enteric Dysfunction in Children

Diarrheal diseases are a major cause of childhood death in resource-poor countries, killing approximately 760,000 children younger than 5 years each year. Although deaths due to diarrhea have declined dramatically, high rates of stunting and malnutrition have persisted. Environmental enteric dysfunction (EED) is a subclinical condition caused by constant fecal-oral contamination with resultant intestinal inflammation and villous blunting. These histological changes were first described in the 1960s, but the clinical effect of EED is only just being recognized in the context of failure of nutritional interventions and oral vaccines in resource-poor countries. We review the existing literature regarding the underlying causes of and potential interventions for EED in children, highlighting the epidemiology, clinical and histologic classification of the entity, and discussing novel biomarkers and possible therapies. Future research priorities are also discussed.

Role of regenerating gene I in claudin expression and barrier function in the small intestine

We have recently shown that loss of the regenerating gene (Reg) I causes susceptibility to nonsteroidal anti-inflammatory drug-induced gastrointestinal damage. However, the mechanism by which Reg I plays a protective role against this pathophysiological condition is unclear. Here, we investigated whether Reg I plays roles in the induction of tight junction proteins and mucosal barrier function in the small intestine. The small-intestinal permeability was evaluated in Reg I-deficient mice by FITC-dextran and transepithelial electrical resistance (TEER) assay. The effect of REG Iα on TEER, claudins expression, and intracellular signaling was examined using Caco2 cells in vitro. Small-intestinal expression of claudins 3 and 4 was investigated in Reg I-deficient mice in vivo. REG I deficiency significantly decreased the expression of claudin 3 in the small-intestinal epithelium. When mice were treated with indomethacin, the serum level of FITC-dextran in Reg I knockout mice was significantly higher than that in wild-type (WT) mice. The level of small-intestinal TEER was significantly decreased in Reg I knockout mice compared with WT mice under normal condition. REG Iα stimulation significantly enhanced the level of TEER in Caco2 cells. Treatment with REG Iα enhanced the expression of claudins 3 and 4 and promoted Sp1, Akt, and ERK phosphorylation in Caco2 cells, whereas these effects were attenuated by treatment with anti-REG Iα antibody. Reg I may play a role in the maintenance of mucosal barrier function by inducing tight junction proteins such as claudins 3 and 4.

EXPRESSION OF REG1Α, GAST AND TGFB1 GENES IN CONDITIONS OF STRESSINDUCED GASTRIC MUCOUS LESIONS DEVELOPMENT AND HEALING IN RATS

Analysis of Reg1a gene expression in rat gastric mucosa under development and healing of stress-induced lesions was carried out. Increased expression of Reg1a was observed after 1 hour of stressor impact - 2,1 times, and achieved the maximum level expression after 3 hours of stress exposure - 3,5 times, that occurred on the background of lipid peroxidation intensification and antioxidant system dysfunction. The sharp decrease in 1,6 and 2 times of Reg1a gene expression was shown in 12 and 24 hours respectively after termination of the stressor action. Analysis of Gast gene expression did not confirm that gastrin stimulated Reg1a expression in gastric mucosa under water immersion restraint stress. The positive correlation between Reg1a and Tgfb1 genes expression was determined in the dynamics of stress-induced gastric lesions’ development and healing, which may indicate the involvement of Tgfb1 to acceleration of lesion’s healing.

Common beans and cowpeas as complementary foods to reduce environmental enteric dysfunction and stunting in Malawian children: study protocol for two randomized controlled trials

Background

Interventions to decrease the burden of childhood malnutrition are urgently needed, as millions of children die annually owing to undernutrition and hundreds of millions more are left cognitively and physically stunted. Environmental enteric dysfunction (EED), a pervasive chronic subclinical inflammatory condition among children that develops when complementary foods are introduced, places them at high risk of stunting, malabsorption, and poor oral vaccine efficacy. Improved interventions to reduce the burden of EED and stunting are expected to markedly improve the nutritional status and survival of children throughout resource-limited settings.

Methods/Design

We will conduct, in parallel, two prospective randomized controlled clinical trials to determine whether common beans or cowpeas improve growth, ameliorate EED, and alter the intestinal microbiome during a high-risk period in the lives of rural Malawian children. Study 1 will enroll children at 6 months of age and randomize them to receive common beans, cowpeas, or a standard complementary food for 6 months. Anthropometry will be compared among the three groups; EED will be assessed using a dual-sugar absorption test and by quantifying human intestinal mRNA for inflammatory messages; and the intestinal microbiota will be characterized by deep sequencing of fecal DNA, to enumerate host microbial populations and their metabolic capacity. Study 2 will enroll children 12–23 months old and follow them for 12 months, with similar interventions and assessments as Study 1.

Discussion

By amalgamating the power of rigorous clinical trials and advanced biological analysis, we aim to elucidate the potential of two grain legumes to reduce stunting and EED in a high-risk population. Legumes have potential as an affordable and effective complementary food intervention, given their cultural acceptability, nutritional content, and agricultural feasibility in sub-Saharan Africa.

Trial registration

Clinicaltrials.gov NCT02472262 and NCT02472301.

Regenerating islet-derived protein 1 inhibits the activation of islet stellate cells isolated from diabetic mice

Emerging evidence indicates that the islet fibrosis is attributable to activation of islet stellate cells (ISCs). In the present study, we compared the differences in biological activity of ISCs isolated from diabetic db/db and non-diabetic db/m mice, and the effects of the regenerating islet-derived protein 1 (Reg1) on ISC function. We showed that ISCs isolated from db/db mice were activated more rapidly than those from db/m mice during culture. Both Reg1 and its putative receptor exostosin-like glycosyltransferase 3 (EXTL3) were highly expressed by diabetic ISCs. Treatment with Reg1 inhibited migration, viability, and synthesis and secretion of Type I Collagen(Col-I), Type III Collagen(Col-III) and Fibronectin(FN) by diabetic ISCs, and this was associated with deactivation of the PI3K/Akt, MAPK/Erk1/2 signaling pathway in an EXTL3-dependent manner. In conclusion, our observations (i) confirmed the presence of fibrogenic stellate cells within pancreatic islets, which are prone to be activated in Type 2 diabetes, and (ii) revealed a potential role for Reg1 in preventing ISC activation.

Interleukin-6/STAT pathway is responsible for the induction of gene expression of REG Iα, a new auto-antigen in Sjögren׳s syndrome patients, in salivary duct epithelial cells

The regenerating gene, Reg, was originally isolated from a rat regenerating islet cDNA library, and its human homolog was named REG Iα. Recently, we reported that REG Iα mRNA as well as its product were overexpressed in ductal epithelial cells in the minor salivary glands of Sjögren׳s syndrome (SS) patients. This study was undertaken to elucidate the role of cytokines and the subsequent intracellular mechanism for induction of REG Iα in the salivary glands of SS patients. We prepared a reporter plasmid containing REG Iα promoter (−1190/+26) upstream of a luciferase reporter gene. The promoter plasmid was introduced by lipofection into human NS-SV-DC and rat A5 salivary ductal cells. The cells were treated with interleukin (IL)-6, IL-8, and a combination of the two. Thereafter transcriptional activity of REG Iα was measured by luciferase assay. We found that IL-6 stimulation, but not IL-8, significantly enhanced the REG Iα promoter activity in salivary ductal cells. Deletion analysis revealed that the region of −141 to −117 of the REG Iα gene was responsible for the promoter activation by IL-6, which contains a consensus sequence for signal transduction and activation of transcription (STAT). The introduction of siRNA for human STAT3 abolished IL-6-induced REG Iα transcription. These results showed that IL-6 stimulation induced REG Iα transcription through STAT3 activation and binding to the consensus sequence of REG Iα promoter in salivary ductal cells. This IL-6/STAT dependent REG Iα induction might play a role in the pathogenesis of SS.

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REG Iα was overexpressed in salivary ductal cells of patients with Sjögren׳s syndrome.

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IL-6 stimulation enhanced the REG Iα gene transcription in salivary ductal cells.

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STAT3 mediated IL-6-induced REG Iα transcription in salivary ductal cells.

Expression of Reg family genes in the gastrointestinal tract of mice treated with indomethacin

Regenerating gene (Reg) family proteins, which are classified into four types, commonly act as trophic and/or antiapoptotic factors in gastrointestinal (GI) diseases. However, it remains unclear how these proteins coordinate their similar roles under such pathophysiological conditions. Here, we investigated the interrelationships of Reg family gene expression with mucosal cell proliferation and apoptosis in nonsteroidal anti-inflammatory drug (NSAID)-induced GI injury. GI injury was induced by subcutaneous injection of indomethacin into Reg I knockout (KO) and wild-type (WT) mice, and its severity was scored histopathologically. Temporal changes in the expression of Reg family genes, mucosal proliferation, and apoptosis were evaluated throughout the GI tract by real-time RT-PCR, Ki-67 immunoreactivity, and TUNEL assay, respectively. Reg I, Reg III family, and Reg IV were predominantly expressed in the upper, middle, and lower GI mucosa, respectively. Expression of Reg I and Reg III family genes was upregulated in specific portions of the GI tract after indomethacin treatment. Ki-67-positive epithelial cells were significantly decreased in the gastric and small-intestinal mucosa of Reg I KO mice under normal conditions. After treatment with indomethacin, the number of TUNEL-positive cells was significantly greater throughout the GI mucosa in Reg I KO mice than in WT mice. Expression of Reg I was independent of that of other Reg family genes in, not only normal GI tissues, but also indomethacin-induced GI lesions. Members of the Reg gene family show distinct profiles of expression in the GI tract, and Reg I independently plays a role in protecting the GI mucosa against NSAID-induced injury.

Effect of REG Iα protein on angiogenesis in gastric cancer tissues

Regenerating gene (REG) Iα is not only overexpressed in a subset of gastric cancers, but also involved in tumor progression. However, the mechanism by which (REG) Iα promotes tumor growth is not fully understood. In the present study, we investigated whether REG Iα plays a role in angiogenesis during the progression of gastric cancers. Expression of REG Iα and its receptor (EXTL3; exostoses like-3) was examined using immunohistochemistry in specimens of human gastric cancer. Microvessel density (MVD) in gastric cancer tissues was evaluated using an image analysis system after CD34 immunostaining. Relationships among clinicopathological features, REG Iα expression and MVD in gastric cancer tissues were analyzed. Effects of REG Iα protein on HUVEC cells in terms of proliferation and anti-apoptosis were assessed by WST-1 assay and FACS, respectively. Furthermore, the intracellular signaling by which REG Iα exerts its biological roles was examined in vitro. REG Iα expression was significantly related to lymph node metastasis and its receptor EXTL3 was ubiquitously expressed in not only the tumor cells, but also the tumor vessel cells in the gastric cancer tissues. MVD was significantly higher in gastric cancers that were REG Iα-positive than in those that were negative. Treatment with REG Iα protein promoted growth and anti-apoptosis through activation of the ERK and Akt signaling pathways in HUVEC cells, whereas these effects were attenuated by treatment with anti-REG Iα -antibody. REG Iα protein may play a role in angiogenesis during progression of gastric cancer.

REG3A accelerates pancreatic cancer cell growth under IL-6-associated inflammatory condition: Involvement of a REG3A-JAK2/STAT3 positive feedback loop

Regenerating gene protein (REG) 3A is a 19 kD secretory pancreas protein with pro-growth function. Previously we demonstrated that overexpression of REG3A, acting as a key molecule for up-regulation of the JAK2/STAT3 pathway, contributed to inflammation-related pancreatic cancer (PaC) development. However the exact network associated with REG3A signaling still remains unclear. Here we determined that exposure of human PaC cells to cytokine IL-6 activated the oncogenic JAK2/STAT3 pathway, which directly upregulated REG3A expression, accelerated cell cycle progression by promoting CyclinD1 expression, and enhancing the expression of the anti-apoptosis Bcl family. Importantly, the activation of REG3A would instead enhance the JAK2/STAT3 pathway to constitute a REG3A-JAK2/STAT3 positive feedback loop, which leads to the amplification of the oncogenic effects of IL-6/JAK2/STAT3, a classic pathway linking to inflammation-related tumorigenesis, ultimately resulting in PaC cell over-proliferation and tumor formation both in vitro and in vivo. Moreover, EGFR was found to mediate the REG3A signal for PaC cell growth and JAK2/STAT3 activation, thus functioning as a REG3A receptor. Collectively, our results provide the first evidence for the presence of the synergistic effect of REG3A and IL-6 on PaC development via a REG3A-JAK2/STAT3 positive feedback loop.

Synergistic activations of REG I α and REG I β promoters by IL-6 and Glucocorticoids through JAK/STAT pathway in human pancreatic β cells

Reg (Regenerating gene) gene was originally isolated from rat regenerating islets and its encoding protein was revealed as an autocrine/paracrine growth factor for β cells. Rat Reg gene is activated in inflammatory conditions for β cell regeneration. In human, although five functional REG family genes (REG Iα, REG Iβ, REG III, HIP/PAP, and REG IV) were isolated, their expressions in β cells under inflammatory conditions remained unclear. In this study, we found that combined addition of IL-6 and dexamethasone (Dx) induced REG Iα and REG Iβ expression in human 1.1B4 β cells. Promoter assay revealed that a signal transducer and activator of transcription- (STAT-) binding site in each promoter of REG Iα (TGCCGGGAA) and REG Iβ (TGCCAGGAA) was essential for the IL-6+Dx-induced promoter activation. A Janus kinase 2 (JAK2) inhibitor significantly inhibited the IL-6+Dx-induced REG Iα and REG Iβ transcription. Electrophoretic mobility shift assay and chromatin immunoprecipitation revealed that IL-6+Dx stimulation increased STAT3 binding to the REG Iα promoter. Furthermore, small interfering RNA-mediated targeting of STAT3 blocked the IL-6+Dx-induced expression of REG Iα and REG Iβ. These results indicate that the expression of REG Iα and REG Iβ should be upregulated in human β cells under inflammatory conditions through the JAK/STAT pathway.

Up-regulated Reg proteins induced by Interleukin-22 treatment ameliorate acute liver injury in rat model

BACKGROUND

The regenerating gene (Reg), encoding lectin-related protein, was originally isolated from a rat regenerating pancreatic islets. Interleukin-22 (IL-22), a recently identified cytokine, is produced by Th 17 cells and natural killer cells. Both of them have been shown to play an important role in controlling tissue repair. But, it is unclear whether the IL-22/Reg axis is involved in liver regeneration and the improvement of liver function in a rat model of acute liver injury.

AIMS

We investigated the expression levels of Reg proteins after IL-22 stimulation in a rat model of acute liver injury, and estimated the effects of Reg proteins ameliorating acute liver injury.

METHODS

Western blot was used to measure the expressions of Reg I, Reg III, Reg IV proteins after treatment with recombinant lentivirus IL-22. At the same time, the expression levels of TB, ALT, AST, endotoxin (ETM), superoxide dismutase (SOD), malondialdehyde (MDA) were detected by related reagents.

RESULTS

In a rat model of acute liver injury, the expression levels of Reg I, Reg III, Reg IV proteins were increased after treatment with IL-22 recombinant lentivirus compared with treatment with lentivirus-empty vector, especially, Reg IV protein expression. Meanwhile, treatment with IL-22 recombinant lentivirus reduced serum levels of TB, ALT, AST, ETM, and decreased MAD levels in rat liver tissues, but increased SOD levels in rat liver tissues.

CONCLUSION

IL-22 stimulation enhanced the expressions of Reg proteins in liver cell, especially, Reg IV protein, and ameliorated liver injury in a rat model of acute liver injury. Reg protein, especially Reg IV protein, might act as a biological mediator of immune cell-derived IL-22 in the recovering mechanism of liver injury.

Infliximab restores the dysfunctional matrix remodeling protein and growth factor gene expression in patients with inflammatory bowel disease

BACKGROUND

Matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), a disintegrin and metalloprotease with thrombospondin motifs [ADAM(TS)s] and growth factors are involved in inflammation and tissue damage and repair, all occurring in inflammatory bowel disease (IBD). We studied the impact of anti-inflammatory therapy with infliximab on mucosal expression of these tissue remodeling genes in patients with IBD.

METHODS

Mucosal gene expression of 23 MMPs, 4 TIMPs, 50 ADAM(TS)s, and 158 growth factors was investigated in 61 patients with IBD before and after the first infliximab therapy and in 12 controls, with microarrays and quantitative RT-PCR. Protein localization, mucosal gelatinase levels, and net gelatinolytic activity were investigated by immunohistochemistry, zymography analysis, and gelatin degradation assay, respectively.

RESULTS

In patients with active IBD before infliximab versus controls, gene expression of many MMPs, TIMPs, ADAM(TS)s, and growth factors was upregulated, whereas colonic expression of MMP28 and TGFA and ileal expression of ADAMDEC1 and AGT were downregulated. After controlling inflammation with infliximab, most gene dysregulations observed at baseline were restored in responders. Increased ratio of MMP1/TIMP1 expression at baseline in active IBD was restored in responders with colonic mucosal healing. With immunohistochemistry, protein localization differences of MMP1, MMP3, REG1A, and TIMP1 were shown between active IBD and control mucosa. With zymography analysis and gelatin degradation assay, higher gelatinase levels and net gelatinolytic activity were measured before infliximab and levels normalized after infliximab.

CONCLUSIONS

Our data suggest that suppression of inflammation results in the arrest of epithelial damage and subsequent mucosal healing. Therefore, the therapeutic potential of agents targeting MMPs or growth factors as primary therapy seems rather complex.

Hes1 promotes the IL-22-mediated antimicrobial response by enhancing STAT3-dependent transcription in human intestinal epithelial cells

Notch signaling plays an essential role in the proliferation and differentiation of intestinal epithelial cells (IECs). We have previously shown that Notch signaling is up-regulated in the inflamed mucosa of ulcerative colitis (UC) and thereby plays an indispensable role in tissue regeneration. Here we show that in addition to Notch signaling, STAT3 signaling is highly activated in the inflamed mucosa of UC. Forced expression of the Notch target gene Hes1 dramatically enhanced the IL-22-mediated STAT3-dependent transcription in human IECs. This enhancement of STAT3-dependent transcription was achieved by the extended phosphorylation of STAT3 by Hes1. Microarray analysis revealed that Hes1-mediated enhancement of IL-22-STAT3 signaling significantly increased the induction of genes encoding antimicrobial peptides, such as REG1A, REG3A and REG3G, in human IECs. Conversely, the reduction of Hes1 protein levels with a γ-secretase inhibitor significantly down-regulated the induction of those genes in IECs, resulting in a markedly poor response to IL-22. Our present findings identify a new role for the molecular function of Hes1 in which the protein can interact with cytokine signals and regulate the immune response of IECs.

Involvement of autoimmunity to REG, a regeneration factor, in patients with primary Sjögren's syndrome

The regenerating gene (Reg) was isolated originally as a gene specifically over-expressed in regenerating pancreatic islets and constitute a growth factor family. Reg gene product (Reg) is important in the pathophysiology of various human inflammatory diseases. Recently, the possible involvement of human REG in the regeneration of salivary ductal epithelial cells of patients with primary Sjögren's syndrome (SS) was reported. However, the expression of the REG family genes in minor salivary glands (MSG) and the occurrence of anti-REG Iα autoantibodies in SS patients were obscured. In this study, we examined the expression of REG family genes in the MSG of SS and screened anti-REG Iα autoantibodies in SS. The mRNA levels of REG family genes in MSG were quantified using real-time reverse transcription-polymerase chain reaction (RT-PCR) and REG Iα expression in the MSG was analysed by immunohistochemistry. The mRNA level of REG Iα in the MSG of SS patients was significantly higher than that of control. REG Iα protein was expressed highly in SS ductal epithelial cells. Anti-REG Iα autoantibodies in the sera were found in 11% of SS. All the MSG in the anti-REG Iα autoantibody-positive group showed REG Iα expression, whereas only 40% showed REG Iα expression in the anti-REG Iα autoantibody-negative group. The anti-REG Iα autoantibody-positive group showed significantly lower saliva secretion and a higher ratio of grade 4 (by Rubin-Holt) in sialography. These data suggest strongly that autoimmunity to REG Iα might play a role in the degeneration of MSG ductal epithelial cells in primary SS.

Overexpression of regenerating gene Iα appears to reflect aberration of crypt cell compartmentalization in sessile serrated adenoma/polyps of the colon

Background

Colorectal sessile serrated adenoma/polyps (SSA/Ps) are characterized by asymmetrical distribution of Ki67-positive cells, which varies among crypts and involves the crypt length to a variable extent; the pattern has been designated as aberration of crypt cell compartmentalization. The regenerating gene (REG) Iα is a cell growth and/or anti-apoptotic factor and its overexpression might be associated with aberration of crypt cell compartmentalization in SSA/Ps. We investigated REG Iα expression in SSA/Ps in comparison to hyperplastic polyps (HPs).

Methods

A total of 64 cases of serrated polyps (≥10 mm in size), including 53 SSA/Ps and 11 HPs, were included in the present study. Immunostaining was performed using a labeled streptavidin-biotin method. REG Iα expression was classified as follows: (i) expression of endocrine cells: grade 0 (a few positive cells) to 3 (marked increase in positive cells); (ii) expression of goblet cells: grade 0 (negative) to 2 (positive for crypts and surface epithelial cells); (iii) staining intensity of goblet cells: grade 0 (negative) to 2 (strong); (iv) staining intensity of crypt (absorptive) cell membranes: grade 0 (negative) to 2 (strong). The presence of aberration of crypt cell compartmentalization was assessed using Ki67 immunostaining.

Results

With regard to the REG Iα expression of endocrine cells, 8 out of 11 HPs (73%) were grade 0, whereas 51 of 53 SSA/Ps (96%) were grade 1 or higher (p < 0.001). With regard to the distribution of REG Iα-immunoreactive goblet cells, 10 of 11 HPs (91%) were grade 1, whereas 50 of 53 SSA/Ps (94%) were grade 2 (p < 0.001). A similar trend was found in the staining intensity of goblet cells or crypt cell membranes (p = 0.011). Aberration of crypt cell compartmentalization was more frequently identified in SSA/Ps (72%) than in HPs (18%; p = 0.002). A significant association was observed between REG Iα overexpression and the aberration of crypt cell compartmentalization in serrated polyps (p = 0.037).

Conclusions

REG Iα overexpression is a characteristic of SSA/Ps, which appears to reflect aberration of crypt cell compartmentalization.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7240956081100040

Reg proteins and their roles in inflammation and cancer of the human digestive system

The regenerating gene (Reg) family is a group of small molecules that includes four members found in various species, although only three are found in human tissues. Their expression is stimulated by certain growth factors or cytokines. The Reg family plays different roles in proliferation, migration, and anti-apoptosis through activating different signaling pathways. Their dysexpression is closely associated with a number of human conditions and diseases such as inflammation and cancer, especially in the human digestive system. Clinically, upregulation of Reg proteins is usually demonstrated in histological sections and sera from cancer patients. Therefore, Reg proteins can predict the progression and prognosis of cancers, especially those of the digestive tract, and can also act as diagnostic markers and therapeutic targets.

Transcriptional analysis of the intestinal mucosa of patients with ulcerative colitis in remission reveals lasting epithelial cell alterations

OBJECTIVE

Ulcerative colitis (UC) is a chronic condition characterised by the relapsing inflammation despite previous endoscopic and histological healing. Our objective was to identify the molecular signature associated with UC remission.

DESIGN

We performed whole-genome transcriptional analysis of colonic biopsies from patients with histologically active and inactive UC, and non-inflammatory bowel disease (non-IBD) controls. Real-time reverse transcriptase-PCR and immunostaining were used for validating selected genes in independent cohorts of patients.

RESULTS

Microarray analysis (n=43) demonstrates that UC patients in remission present an intestinal transcriptional signature that significantly differs from that of non-IBD controls and active patients. Fifty-four selected genes were validated in an independent cohort of patients (n=30). Twenty-nine of these genes were significantly regulated in UC-in-remission subjects compared with non-IBD controls, including a large number of epithelial cell-expressed genes such as REG4, S100P, SERPINB5, SLC16A1, DEFB1, AQP3 and AQP8, which modulate epithelial cell growth, sensitivity to apoptosis and immune function. Expression of inflammation-related genes such as REG1A and IL8 returned to control levels during remission. REG4, S100P, SERPINB5 and REG1A protein expression was confirmed by immunohistochemistry (n=23).

CONCLUSIONS

Analysis of the gene signature associated with remission allowed us to unravel pathways permanently deregulated in UC despite histological recovery. Given the strong link between the regulation of some of these genes and the growth and dissemination of gastrointestinal cancers, we believe their aberrant expression in UC may provide a mechanism for epithelial hyper-proliferation and, in the context of malignant transformation, for tumour growth.

REG1B as a predictor of childhood stunting in Bangladesh and Peru

BACKGROUND

Undernutrition remains a significant problem worldwide, with environmental enteropathy implicated as a contributing factor. An understanding of the pathogenesis and identification of children at risk are critical to the design of more-effective interventions.

OBJECTIVE

The stool regenerating gene 1β (REG1B) protein, which is a putative measure of intestinal injury and repair, was tested as a noninvasive biomarker of future childhood stunting.

DESIGN

A total of 222 children from Bangladesh and 97 children from Peru, who were from impoverished communities, were followed from birth through 24 mo of age with anthropometric measures obtained every 3 mo. Stool REG1B protein concentrations were obtained by using an REG1B polyclonal-polyclonal ELISA at 3 mo of age. We tested for the ability of REG1B to forecast future anthropometric shortfalls, independent of known predictors of undernutrition of family income and baseline height and weight.

RESULTS

In the Bangladesh cohort of 222 children, higher REG1B concentrations at month 3 were significantly and independently associated with a growth shortfall in a linear regression analysis at months 9, 12, 18, 21, and 24 and, in the Peru cohort, at months 12, 15, 18, 21, and 24. With the use of a mixed model for repeated measurements, higher stool REG1B concentrations at 3 mo were also independently predictive of a lower future length-for-age z score through 24 mo of age (Bangladesh P = 0.006; Peru P = 0.058).

CONCLUSION

The ability of fecal REG1B to predict growth shortfall in independent cohorts of impoverished children from the developing world offers promise as a malnutrition biomarker and supports a role for environmental enteropathy in the pathogenesis of growth shortfall.

Gene signature distinguishes patients with chronic ulcerative colitis harboring remote neoplastic lesions

BACKGROUND

Individuals with ulcerative colitis (UC) are at increased risk for colorectal cancer. The standard method of surveillance for neoplasia in UC by colonoscopy is invasive and can miss flat lesions. We sought to identify a gene expression signature in nondysplastic mucosa without active inflammation that could serve as a marker for remote neoplastic lesions.

METHODS

Gene expression was analyzed by complementary DNA microarray in 5 normal controls, 4 UC patients without dysplasia, and 11 UC patients harboring remote neoplasia. Common gene ontology pathways of significantly differentially expressed genes were identified. Expression of genes which were progressively and significantly upregulated from controls to UC without neoplasia, to UC with remote neoplasia were evaluated by real-time polymerase chain reaction. Several gene products were also examined by immunohistochemistry.

RESULTS

Four hundred and sixty-eight genes were significantly upregulated, and 541 genes were significantly downregulated in UC patients with neoplasia compared with UC patients without neoplasia. Nine genes (ACSL1, BIRC3, CLC, CREM, ELTD1, FGG, S100A9, THBD, and TPD52L1) were progressively and significantly upregulated from controls to nondysplastic UC to UC with neoplasia. Immunostaining of proteins revealed increased expression of S100A9 and REG1α in UC-associated cancer and in nondysplastic tissue from UC patients harboring remote neoplasia compared with UC patients without neoplasia and controls.

CONCLUSIONS

Gene expression changes occurring as a field effect in the distal colon of patients with chronic UC identify patients harboring remote neoplastic lesions. These markers may lead to a more accurate and less invasive method of detection of neoplasia in patients with inflammatory bowel disease.

Regulation of colon gene expression by vitamin B6 supplementation

SCOPE

Previous studies have shown that vitamin B6 supplementation suppresses the development of colonic aberrant crypt foci (ACF), precursor lesions of colon cancer, and cell proliferation in mice receiving the colonic carcinogen, azoxymethane (AOM). This study investigated the molecular mechanism of these effects of dietary vitamin B6.

METHODS AND RESULTS

To date, the mechanism by which ACFs develop is not yet fully understood. In a search for factors that play a critical role during ACF development, we examined colon gene expression during early stage of ACF development in AOM-treated mice using DNA microarray analysis. AOM treatment significantly upregulated mRNA closely related to mast cell and cytotoxic T-cell activity. This study also investigated the effect of vitamin B6 supplementation on colon gene expression in AOM-treated mice. We found that vitamin B6 supplementation downregulates Cd8a and Ccl8 mRNA expression, suggesting these candidate genes may play a protective role against colonic ACF development. Furthermore, we examined genomic affects of dietary vitamin B6, and showed that Reg3γ mRNA expression in colons is downregulated by vitamin B6.

CONCLUSION

This study provides an insight into the genomic activities of dietary vitamin B6 that may be protective against colon tumor development.

Expression profile of genes involved in pathogenesis of pediatric Crohn's disease

BACKGROUND AND AIM

Expression profiling of genes specific to pediatric Crohn's Disease (CD) patients was performed to elucidate the molecular mechanisms underlying disease cause and pathogenesis at disease onset.

METHODS

We used suppressive subtractive hybridization (SSH) and differential screening analysis to profile the mRNA expression patterns of children with CD and age- and sex-matched controls without inflammatory bowel disease (IBD).

RESULTS

Sequence analysis of 1000 clones enriched by SSH identified 75 functionally annotated human genes, represented by 430 clones. The 75 genes have potential involvement in gene networks, such as antigen presentation, inflammation, infection mechanism, connective tissue development, cell cycle and cancer. Twenty-eight genes were previously described in association with CD, while 47 were new genes not previously reported in the context of IBD. Additionally, 29 of the 75 genes have been previously implicated in bacterial and viral infections. Quantitative real-time reverse transcription polymerase chain reaction performed on ileal-derived RNA from 13 CD and nine non-IBD patients confirmed the upregulation of extracellular matrix gene MMP2 (P = 0.001), and cell proliferation gene REG1A (P = 0.063) in our pediatric CD cohort.

CONCLUSION

The retrieval of 28 genes previously reported in association with adult CD emphasizes the importance of these genes in the pediatric setting. The observed upregulation of REG1A and MMP2, and their known impact on cell proliferation and extracellular matrix remodeling, agrees with the clinical behavior of the disease. Moreover, the expressions of bacterial- and virus-related genes in our CD-patient tissues support the concept that microbial agents are important in the etiopathogenesis of CD.

High-speed atomic force microscopy coming of age

High-speed atomic force microscopy (HS-AFM) is now materialized. It allows direct visualization of dynamic structural changes and dynamic processes of functioning biological molecules in physiological solutions, at high spatiotemporal resolution. Dynamic molecular events unselectively appear in detail in an AFM movie, facilitating our understanding of how biological molecules operate to function. This review describes a historical overview of technical development towards HS-AFM, summarizes elementary devices and techniques used in the current HS-AFM, and then highlights recent imaging studies. Finally, future challenges of HS-AFM studies are briefly discussed.

Regenerating gene (REG) 1 alpha promotes pannus progression in patients with rheumatoid arthritis

INTRODUCTION

A protein analysis using mass spectrometry revealed the existence of serum proteins with significant quantitative changes after the administration of infliximab. Among these proteins, regenerating gene (REG) 1α appears to be related to the pathogenesis of rheumatoid arthritis (RA). Therefore, the present study was conducted to examine the mechanism of REG1α in RA disease progression.

METHODS

Serum samples were collected from RA patients and normal healthy controls. REG1α expression was evaluated by ELISA, RT-PCR, and indirect immunofluorescence microscopy. The functions of REG1α on synovial fibroblasts with regard to apoptosis, receptor activator of NF-κB ligand (RANKL) expression, and cellar proliferation were evaluated using siRNA to inhibit the intrinsic REG1α mRNA expression.

RESULTS

The serum concentrations of REG1α in RA patients were higher than in normal healthy controls. The high expression of REG1α was also observed in the synovial tissue of RA patients compared to those of osteoarthropathy patients. In addition, tumor necrosis factor-α (TNF-α) upregulated REG1α expression in the synovial fibroblasts cell line (MH7A). Inhibition of REG1α expression suppressed the induction of RANKL expression by TNF-α. Furthermore, exogenous recombinant REG1α protein inhibited apoptosis and promoted cell proliferation in MH7A cells. These effects were abolished in the REG1α-siRNA MH7A cells.

CONCLUSION

The present data suggest that TNF-α induces aberrant REG1α expression and that REG1α plays an important role in aberrant cell proliferation and RANKL expression of synovial fibroblasts, ultimately resulting in pannus formation. Restoration of normal physiological REG1α expression may contribute to disease amelioration.

Activation of REG family proteins in colitis

AIMS

To do a genome-wide gene expression study of active and inactive ulcerative colitis and Crohn's disease (inflammatory bowel disease--IBD) and examine the most differentially expressed genes. As the study showed an extreme upregulation of all regenerating islet-derived genes (REG proteins) in active IBD, we further studied the expression of REGs on protein level in active and inactive IBD, as well as in non-IBD (pseudomembranous) colitis.

METHODS

Microarray analysis was done on a total of 100 pinch biopsy samples from healthy controls and patients with Crohn's disease or ulcerative colitis. Tissue samples from IBD and pseudomembranous colitis were examined with routine histology and immunohistochemical analysis for REGIα, REGIV, DEFA6, and serotonin.

RESULTS

REG mRNAs were up to 83 times overexpressed in diseased mucosa compared with mucosa from healthy individuals. REGIα and REGIV were overexpressed at immunohistochemistry and located to different mucosal cell types. REGIα was expressed in basal half of crypts, REGIV in mid and outer parts of crypts and in surface epithelium and seems to be stored in, and secreted from, goblets. Pseudomembranous colitis samples showed similar staining patterns, and some IBD samples stained REG positive without inflammation on routine histology.

CONCLUSIONS

All REG family mRNAs are upregulated in IBD. REGIα and REGIV have different cellular localization, possibly reflecting different biological functions. REG protein expression also in pseudomembranous colitis shows that REG family proteins are regulated in inflammatory injury and repair, not specifically for IBD as previously thought.

The regenerating gene iα is overexpressed in atrophic gastritis rats with hypergastrinemia

The role of gastrin on the development of atrophic gastritis (AG) and its relationship with the expression of RegIα  in vivo remain unclear. We established experimental AG in rats by combination administration with sodium salicylate, alcohol, and deoxycholate sodium. The mean score of inflammation in gastric antrum in AG rats was significantly elevated (P < 0.05), while the number of glands dramatically decreased (P < 0.05). In addition, the cell proliferation in gastric glands was increased in experimental AG rats, as determined by immunohistochemistry staining of PCNA and GS II. The level of serum gastrin in AG rats was significantly elevated relative to that of normal rats (P < 0.01). Moreover, the expression of RegIα protein and its receptor mRNA was increased in gastric tissues in AG rats (P < 0.05). Taken together, we demonstrated that the overexpression of Reglα is related with hypergastrinemia in AG rats.

Regenerating I messenger RNA and protein expression in the failing human testis: a potential molecular prognostic marker of seminoma

Infertility has been stated as a risk factor for testicular cancer; but currently, there is no prognostic indicator of tumor development from the pathologic testis with impaired spermatogenesis. Regenerating proteins are expressed in many human tissues including the testis, and their role in carcinogenesis has been well documented. In the present work, regenerating I messenger RNA and protein expression and cellular protein localization were studied in testicular biopsies of patients with normal (obstructive azoospermia) or impaired spermatogenesis (nonobstructive azoospermia) and in seminoma testis by quantitative reverse transcriptase-polymerase chain reaction, Western blot, and immunofluorescence analyses. No significant differences in regenerating I transcripts were reported between the 3 groups studied. However, regenerating I protein was highly expressed in pure seminoma and in placental-like alkaline phosphatase-positive seminiferous tubules with in situ carcinoma. Regenerating I protein levels measured by Western blotting increased from the placental-like alkaline phosphatase-negative distal region of the seminoma to the pure placental-like alkaline phosphatase-positive tumoral region. Importantly, although cells localized in seminiferous tubules of obstructive azoospermic patients with normal spermatogenesis were very slightly labeled, persisting germ, Sertoli, and myoid cells and fibrous tissues were strongly regenerating I positive in seminiferous tubules of nonobstructive azoospermia. These results suggest the possibility to use regenerating I as a prognostic marker of tumoral development in the infertile testis.

Bifidobacterium longum supplementation improved high-fat-fed-induced metabolic syndrome and promoted intestinal Reg I gene expression

Recent evidence suggests that intestinal Bifidobacterium species (spp.) positively correlates with improved insulin resistance and obesity, and this might be linked to metabolic inflammation. The expression of intestinal REG (regenerating) family proteins which are widely involved in inflammatory bowel disease and diabetes are still unknown in metabolic syndrome. Hence, we investigated the effects of Bifidobacterium longum (BIF) supplementation on metabolic parameters, intestinal function and expression of Reg family genes in a rat model of metabolic syndrome induced by a high-fat (HF) diet. We specifically increased the gut bifidobacterial content of HF-fed rats through BIF supplementation. Compared with the normal chow-fed control rats, HF feeding significantly reduced intestinal Bifidobacterium. As expected, BIF supplementation fed rats had totally restored quantities of Bifidobacterium. HF diet-fed rats showed significant increase in body weight, fat deposits, systolic blood pressure, fasting glucose, fasting triglycerides and reduced insulin sensitivity, while increases of intestinal Bifidobacterium did improve HF-diet-induced metabolic disorders. HF feeding led to significantly higher levels of the plasma lipopolysaccharide, interleukin-1β and intestinal myeloperoxidase, as well as intestinal inflammatory activity index, while these parameters were normalized to the control levels in the HF + BIF-treated rats. The levels of RegI mRNA and protein in the HF + BIF group were significantly higher than the control and the HF groups. Increasing Bifidobacterium in the gut improved HF-fed-induced metabolic syndrome by reducing metabolic endotoxin concentrations and intestinal inflammation, as well as upgrading the expression of intestinal Reg I as a regulator of growth factor.

The expression of REG 1A and REG 1B is increased during acute amebic colitis

Entamoeba histolytica, a protozoan parasite, is an important cause of diarrhea and colitis in the developing world. Amebic colitis is characterized by ulceration of the intestinal mucosa. We performed microarray analysis of intestinal biopsies during acute and convalescent amebiasis in order to identify genes potentially involved in tissue injury or repair. Colonic biopsy samples were obtained from 8 patients during acute E. histolytica colitis and again 60 days after recovery. Gene expression in the biopsies was evaluated using microarray, and confirmed by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). REG 1A and REG 1B were the most up-regulated of all genes in the human intestine in acute versus convalescent E. histolytica disease: as determined by microarray, the levels of induction were 7.4-fold and 10.7 fold for REG 1A and B; p=0.003 and p=0.006 respectively. Increased expression of REG 1A and REG 1B protein in the colonic crypt epithelial cells during acute amebiasis was similarly observed by immunohistochemistry. Because REG 1 protein is anti-apoptotic and pro-proliferative, and since E. histolytica induces apoptosis of the intestinal epithelium as part of its disease process, we next tested if REG 1 might be protective during amebiasis by preventing parasite-induced apoptosis. Intestinal epithelial cells from REG 1-/- mice were found to be more susceptible to spontaneous, and parasite-induced, apoptosis in vitro (p=0.03). We concluded that REG 1A and REG 1B were upregulated during amebiasis and may function to protect the intestinal epithelium from parasite-induced apoptosis.

DMBT1 is a novel gene induced by IL-22 in ulcerative colitis

BACKGROUND

Interleukin (IL)-22 is a recently identified cytokine that is suggested to play pivotal roles in various inflammatory diseases. Although the IL-22 receptor 1 (IL-22R1) is restrictively expressed in epithelial cells in the colon, the role of IL-22 in colonic diseases still remains unclear. In this study microarray analyses revealed that deleted in malignant brain tumors 1 (DMBT1) is a novel upregulated gene in IL-22-stimulated colon cancer cells. Therefore, we investigated the involvement of DMBT1 and IL-22 in ulcerative colitis (UC) tissues and examined the mechanism regulating the expression of DMBT1 in response to IL-22 stimulation.

METHODS

Changes of gene expression in IL-22-stimulated SW403 cells were investigated by microarray analyses. The effects of IL-22 on DMBT1 expression were examined in SW403 cells using a small interfering RNA (si)RNA for STAT3 or inhibitors for MEK, PI3K, and nuclear factor kappa B (NF-κB). The element responsible for IL-22-induced DMBT1 promoter activation was determined by a promoter deletion and electrophoretic mobility shift assay (EMSA). Expression of IL-22, IL-22R1, and DMBT1 in UC tissues was analyzed by real-time reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemistry.

RESULTS

IL-22 treatment enhanced the expression of DMBT1 through STAT3 tyrosine phosphorylation and NF-κB activation in colon cancer cells. The IL-22-responsive element was located between -187 and -179 in the DMBT1 promoter region. In the UC mucosa the levels of DMBT1 and IL-22 mRNA expression were significantly enhanced and positively correlated, the numbers of IL-22-positive lymphocytes were increased, and the expression of IL-22R1 and DMBT1 was enhanced in the inflamed epithelium.

CONCLUSIONS

The IL-22/DMBT1 axis may play a pivotal role in the pathophysiology of UC.

Deciphering the structure, growth and assembly of amyloid-like fibrils using high-speed atomic force microscopy

Formation of fibrillar structures of proteins that deposit into aggregates has been suggested to play a key role in various neurodegenerative diseases. However mechanisms and dynamics of fibrillization remains to be elucidated. We have previously established that lithostathine, a protein overexpressed in the pre-clinical stages of Alzheimer's disease and present in the pathognomonic lesions associated with this disease, form fibrillar aggregates after its N-terminal truncation. In this paper we visualized, using high-speed atomic force microscopy (HS-AFM), growth and assembly of lithostathine protofibrils under physiological conditions with a time resolution of one image/s. Real-time imaging highlighted a very high velocity of elongation. Formation of fibrils via protofibril lateral association and stacking was also monitored revealing a zipper-like mechanism of association. We also demonstrate that, like other amyloid ß peptides, two lithostathine protofibrils can associate to form helical fibrils. Another striking finding is the propensity of the end of a growing protofibril or fibril to associate with the edge of a second fibril, forming false branching point. Taken together this study provides new clues about fibrillization mechanism of amyloid proteins.

Upregulation of REG Ialpha accelerates tumor progression in pancreatic cancer with diabetes

Diabetes is now generally accepted as a crucial event in the process of pancreatic cancer (PaC). However, molecular mechanisms underlying the relationship between diabetes and PaC are not fully understood. Regenerating gene (REG) Ialpha is a growth factor affecting pancreatic islet beta cells, and it has been shown to be involved in the carcinogenesis in gastrointestinal tract. It is rational to speculate that REG Ialpha plays a potential role in the pathogenesis of PaC with diabetes. The aim of this study was to evaluate the REG Ialpha protein expression profile in PaC with and without diabetes, and define the contribution of REG Ialpha on PaC development. We found that REG Ialpha protein preferentially expressed in cancerous tissues of PaC patients with diabetes by Western blot. REG Ialpha positive cancer cells in PaC with diabetes (n = 38) was significantly higher than that in subjects without diabetes (n = 42, p < 0.05) by immunohistochemical analysis. Furthermore, we found that overexpression of REG Ialpha protein in PaC cell lines resulted in accelerated cell proliferation and consequently tumor growth, both in vitro and in vivo. The findings suggest that REG Ialpha may act as one of the tumor promoter and contribute to the aggressive nature of PaC, especially in the subpopulation with diabetes. This study would shed new insights for understanding the molecular mechanisms underlying the link between diabetes and PaC.

RegIV expression showing specificity to gastrointestinal tract and its potential role in diagnosing digestive tract neuroendocrine tumor

Regenerating gene IV (RegIV), a member of the regenerating gene family discovered in 2001, has been found to be involved in malignancy in several different organs including the stomach, colorectum, pancreas and prostate, but the overall expression profile of RegIV has not been reported. To learn more about RegIV, we evaluated its distribution by immunohistochemistry (IHC) in a total of 360 samples including 24 types of normal tissue, 40 benign and malignant lesions, and 18 neuroendocrine tumors. We found that in normal tissues, in addition to its relative specificity for the gastrointestinal tract, RegIV was detected in the adrenal gland and mammary gland. Among all the malignancies of various histological types under evaluation, RegIV was found mostly in adenocarcinomas. Studies on additional sets of colorectal tumor samples showed that RegIV expression was predominant in colorectal adenoma (87.5%) and peritumoral tissue (100%) but not in cancer tissue (30.8%). Among neuroendocrine tumors, RegIV had a relatively restricted expression to those of digestive system.

RegIV potentiates colorectal carcinoma cell migration and invasion via its CRD domain

The RegIV gene is differentially expressed in cancer and noncancerous cells. In this study, we investigated the role of RegIV and its CRD domain in the invasion and migration of human colorectal carcinoma LoVo cells. Recombinant plasmids, pcDNA3.1-RegIV and pcDNA3.1-RegIV CRD, were constructed and transfected into LoVo cells. The in vivo RegIV and RegIV CRD mRNA and protein levels were then analyzed by reverse transcriptase-polymerase chain reaction and immunocytochemistry, respectively. Cell proliferation was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and flat plate colony-forming assays, and apoptosis was measured by flow cytometry. Cell migration and invasion were assessed with a Transwell chamber. A high level of RegIV and RegIV carbohydrate-recognition domain (CRD) expression was demonstrated in RegIV and RegIV CRD-transfected cells. There were no differences in cell proliferation, colony formation, and apoptosis between the LoVo/RegIV and untreated LoVo cells (P > 0.05). However, the LoVo/RegIV cells, but not LoVo/RegIV CRD cells, displayed greater migration and invasion abilities compared to the empty vector and untreated LoVo cells. The migrated cell numbers of the LoVo/RegIV, LoVo/RegIV CRD, LoVo/empty vector, and control LoVo groups were 247.00 +/- 10.61, 146.27 +/- 6.81, 151.16 +/- 7.18, and 149.65 +/- 6.53 cells per field, respectively (P < 0.05). The invasion cell numbers of the four groups were 57.00 +/- 3.00, 31.53 +/- 2.72, 30.3 +/- 2.07, and 32.16 +/- 2.30 cells per field, respectively. RegIV enhances LoVo cell migration and invasion, and its CRD domain is critical for these effects.