Keratins in colorectal epithelial function and disease

Exploring Predictive Biomarkers of Relapse in Ulcerative Colitis: A Proteomics Approach

INTRODUCTION AND AIMS

Risk stratification of subjects with a history of inflammatory bowel disease (IBD) into those likely to relapse and those who will remain quiescent continues to be a significant challenge. The aim of this study was to investigate whether certain proteomic signature profiles or biomarkers during remission are associated with future disease relapse in patients with ulcerative colitis (UC).

METHODS

Endoscopic rectal samples from patients with UC in clinical, endoscopic, and histological remission at index endoscopy were collected, as well as samplers from normal control individuals. The patients were stratified to early relapsers (ERs) if they developed clinical signs of UC flare within 6 months of index endoscopy or nonrelapsers (NRs) if there was no relapse after 36 months of follow-up. The pooled rectal samples from ERs, NRs, and control individuals were subjected to nano-liquid chromatography and tandem mass spectrometry as per standard iTRAQ (isobaric tags for relative and absolute quantitation) workflow methodology. Selected proteomics-yielded candidates were subjected to orthogonal validation via immunoblotting, in a biomarker discovery exercise.

RESULTS

Sixty-one patients were included, of whom 8 had clinical relapse within 6 months from the index endoscopy, and 43 patients had no clinical symptoms of relapse within the 36-month follow-up period. Ten patients who had clinical signs of relapse between 6 and 36 months were excluded. Seventeen control individuals were also included. Soluble proteomics analyses between ERs, NRs, and control individuals revealed a series of upregulated and downregulated proteins. Following orthogonal validation, upregulated TRX (P = .001) and IGHA1 (P = .001) were observed in ERs relative to NRs.

CONCLUSIONS

Several novel candidate tissue biomarkers have been identified in this study, which could discriminate patients with UC at risk of early relapse from those in long-term sustained remission. Our findings may pave the way for pre-emptive UC disease monitoring and therapeutic decision making.

Transcriptomic Maps of Colorectal Liver Metastasis: Machine Learning of Gene Activation Patterns and Epigenetic Trajectories in Support of Precision Medicine

The molecular mechanisms of the liver metastasis of colorectal cancer (CRLM) remain poorly understood. Here, we applied machine learning and bioinformatics trajectory inference to analyze a gene expression dataset of CRLM. We studied the co-regulation patterns at the gene level, the potential paths of tumor development, their functional context, and their prognostic relevance. Our analysis confirmed the subtyping of five liver metastasis subtypes (LMS). We provide gene-marker signatures for each LMS, and a comprehensive functional characterization that considers both the hallmarks of cancer and the tumor microenvironment. The ordering of CRLMs along a pseudotime-tree revealed a continuous shift in expression programs, suggesting a developmental relationship between the subtypes. Notably, trajectory inference and personalized analysis discovered a range of epigenetic states that shape and guide metastasis progression. By constructing prognostic maps that divided the expression landscape into regions associated with favorable and unfavorable prognoses, we derived a prognostic expression score. This was associated with critical processes such as epithelial-mesenchymal transition, treatment resistance, and immune evasion. These factors were associated with responses to neoadjuvant treatment and the formation of an immuno-suppressive, mesenchymal state. Our machine learning-based molecular profiling provides an in-depth characterization of CRLM heterogeneity with possible implications for treatment and personalized diagnostics.

Keratin 7 expression in different anatomical parts of colonic epithelium in inflammatory bowel diseases and its prognostic value: a 3-year follow-up study

The diagnosis of inflammatory bowel diseases (IBD) may be challenging and their clinical course, characterized by relapses and spontaneous or drug-induced remissions, is difficult to predict. Novel prognostic biomarkers are needed. Keratin 7 (K7) is a cytoskeletal intermediate filament protein which is not normally expressed in the colonic epithelium. It was recently shown that K7 expression in the colonic epithelium is associated with ulcerative colitis and Crohn's disease, the two main subtypes of IBD. Here we investigated IBD associated K7 neo-expression in different regions of colon and terminal ileum. The correlation of the K7 expression with the inflammatory activity of the epithelium was analyzed in each region. The prognostic value of K7 was estimated by comparing the clinical disease activity after 3 years with the K7 expression at the time of enrollment. Our data shows that the level of K7 expression in inflamed epithelium varies depending on the anatomical region and it is the most pronounced in ascending and descending colon, but it did not predict the severity of IBD for the following 3 years. These results warrant future studies focusing on the biological role of K7 in colon and its utilization as potential IBD biomarker.

Roles of Keratins in Intestine

Keratins make up a major portion of epithelial intermediate filament proteins. The widely diverse keratins are found in both the small and large intestines. The human intestine mainly expresses keratins 8, 18, 19, and 20. Many of the common roles of keratins are for the integrity and stability of the epithelial cells. The keratins also protect the cells and tissue from stress and are biomarkers for some diseases in the organs. Although an increasing number of studies have been performed regarding keratins, the roles of keratin in the intestine have not yet been fully understood. This review focuses on discussing the roles of keratins in the intestine. Diverse studies utilizing mouse models and samples from patients with intestinal diseases in the search for the association of keratin in intestinal diseases have been summarized.

Molecular Network Analyses Implicate Death-Associated Protein Kinase 3 (DAPK3) as a Key Factor in Colitis-Associated Dysplasia Progression

BACKGROUND

Ulcerative colitis (UC) is a progressive disorder that elevates the risk of colon cancer development through a colitis-dysplasia-carcinoma sequence. Gene expression profiling of colitis-associated lesions obtained from patients with varied extents of UC can be mined to define molecular panels associated with colon cancer development.

METHODS

Differential gene expression profiles of 3 UC clinical subtypes and healthy controls were developed for the GSE47908 microarray data set of healthy controls, left-sided colitis, pancolitis, and colitis-associated dysplasia (CAD) using limma R.

RESULTS

A gene ontology enrichment analysis of differentially expressed genes (DEGs) revealed a shift in the transcriptome landscape as UC progressed from left-sided colitis to pancolitis to CAD, from being immune-centric to being cytoskeleton-dependent. Hippo signaling (via Yes-associated protein [YAP]) and Ephrin receptor signaling were the top canonical pathways progressively altered in concert with the pathogenic progression of UC. A molecular interaction network analysis of DEGs in left-sided colitis, pancolitis, and CAD revealed 1 pairwise line, or edge, that was topologically important to the network structure. This edge was found to be highly enriched in actin-based processes, and death-associated protein kinase 3 (DAPK3) was a critical member and sole protein kinase member of this network. Death-associated protein kinase 3 is a regulator of actin-cytoskeleton reorganization that controls proliferation and apoptosis. Differential correlation analyses revealed a negative correlation for DAPK3-YAP in healthy controls that flipped to positive in left-sided colitis. With UC progression to CAD, the DAPK3-YAP correlation grew progressively more positive.

CONCLUSION

In summary, DAPK3 was identified as a candidate gene involved in UC progression to dysplasia.

Epithelial to mesenchymal transition influences fibroblast phenotype in colorectal cancer by altering miR-200 levels in extracellular vesicles

Colorectal cancer (CRC) with a mesenchymal gene expression signature has the greatest propensity for distant metastasis and is characterised by the accumulation of cancer‐associated fibroblasts in the stroma. We investigated whether the epithelial to mesenchymal transition status of CRC cells influences fibroblast phenotype, with a focus on the transfer of extracellular vesicles (EVs), as a controlled means of cell–cell communication. Epithelial CRC EVs suppressed TGF‐β‐driven myofibroblast differentiation, whereas mesenchymal CRC EVs did not. This was driven by miR‐200 (miR‐200a/b/c, ‐141), which was enriched in epithelial CRC EVs and transferred to recipient fibroblasts. Ectopic miR‐200 expression or ZEB1 knockdown, in fibroblasts, similarly suppressed myofibroblast differentiation. Supporting these findings, there was a strong negative correlation between miR‐200 and myofibroblastic markers in a cohort of CRC patients in the TCGA dataset. This was replicated in mice, by co‐injecting epithelial or mesenchymal CRC cells with fibroblasts and analysing stromal markers of myofibroblastic phenotype. Fibroblasts from epithelial tumours contained more miR‐200 and expressed less ACTA2 and FN1 than those from mesenchymal tumours. As such, these data provide a new mechanism for the development of fibroblast heterogeneity in CRC, through EV‐mediated transfer of miRNAs, and provide an explanation as to why CRC tumours with greater metastatic potential are CAF rich.

Emerging role of protein modification in inflammatory bowel disease

The onset of inflammatory bowel disease (IBD) involves many factors, including environmental parameters, microorganisms, and the immune system. Although research on IBD continues to expand, the specific pathogenesis mechanism is still unclear. Protein modification refers to chemical modification after protein biosynthesis, also known as post-translational modification (PTM), which causes changes in the properties and functions of proteins. Since proteins can be modified in different ways, such as acetylation, methylation, and phosphorylation, the functions of proteins in different modified states will also be different. Transitions between different states of protein or changes in modification sites can regulate protein properties and functions. Such modifications like neddylation, sumoylation, glycosylation, and acetylation can activate or inhibit various signaling pathways (e.g., nuclear factor-‍κB (NF-‍κB), extracellular signal-regulated kinase (ERK), and protein kinase B (AKT)) by changing the intestinal flora, regulating immune cells, modulating the release of cytokines such as interleukin-1β (IL-‍‍1β), tumor necrosis factor-α (TNF‍-‍α), and interferon-‍γ (IFN-‍γ), and ultimately leading to the maintenance of the stability of the intestinal epithelial barrier. In this review, we focus on the current understanding of PTM and describe its regulatory role in the pathogenesis of IBD.

Integrated Single-cell and Plasma Proteomic Modeling to Predict Surgical Site Complications: A Prospective Cohort Study

OBJECTIVE

The aim of this study was to determine whether single-cell and plasma proteomic elements of the host's immune response to surgery accurately identify patients who develop a surgical site complication (SSC) after major abdominal surgery.

SUMMARY BACKGROUND DATA

SSCs may occur in up to 25% of patients undergoing bowel resection, resulting in significant morbidity and economic burden. However, the accurate prediction of SSCs remains clinically challenging. Leveraging high-content proteomic technologies to comprehensively profile patients' immune response to surgery is a promising approach to identify predictive biological factors of SSCs.

METHODS

Forty-one patients undergoing non-cancer bowel resection were prospectively enrolled. Blood samples collected before surgery and on postoperative day one (POD1) were analyzed using a combination of single-cell mass cytometry and plasma proteomics. The primary outcome was the occurrence of an SSC, including surgical site infection, anastomotic leak, or wound dehiscence within 30 days of surgery.

RESULTS

A multiomic model integrating the single-cell and plasma proteomic data collected on POD1 accurately differentiated patients with (n = 11) and without (n = 30) an SSC [area under the curve (AUC) = 0.86]. Model features included coregulated proinflammatory (eg, IL-6- and MyD88- signaling responses in myeloid cells) and immunosuppressive (eg, JAK/STAT signaling responses in M-MDSCs and Tregs) events preceding an SSC. Importantly, analysis of the immunological data obtained before surgery also yielded a model accurately predicting SSCs (AUC = 0.82).

CONCLUSIONS

The multiomic analysis of patients' immune response after surgery and immune state before surgery revealed systemic immune signatures preceding the development of SSCs. Our results suggest that integrating immunological data in perioperative risk assessment paradigms is a plausible strategy to guide individualized clinical care.

Parity-induced changes to mammary epithelial cells control NKT cell expansion and mammary oncogenesis

Pregnancy reprograms mammary epithelial cells (MECs) to control their responses to pregnancy hormone re-exposure and carcinoma progression. However, the influence of pregnancy on the mammary microenvironment is less clear. Here, we used single-cell RNA sequencing to profile the composition of epithelial and non-epithelial cells in mammary tissue from nulliparous and parous female mice. Our analysis indicates an expansion of γδ natural killer T-like immune cells (NKTs) following pregnancy and upregulation of immune signaling molecules in post-pregnancy MECs. We show that expansion of NKTs following pregnancy is due to elevated expression of the antigen-presenting molecule CD1d on MECs. Loss of CD1d expression on post-pregnancy MECs, or overall lack of activated NKTs, results in mammary oncogenesis. Collectively, our findings illustrate how pregnancy-induced changes modulate the communication between MECs and the immune microenvironment and establish a causal link between pregnancy, the immune microenvironment, and mammary oncogenesis.

Identification of loci associated with pathological outcomes in Holstein cattle infected with Mycobacterium avium subsp. paratuberculosis using whole-genome sequence data

Bovine paratuberculosis (PTB), caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic granulomatous enteritis that affects cattle worldwide. According to their severity and extension, PTB-associated histological lesions have been classified into the following groups; focal, multifocal, and diffuse. It is unknown whether these lesions represent sequential stages or divergent outcomes. In the current study, the associations between host genetic and pathology were explored by genotyping 813 Spanish Holstein cows with no visible lesions (N = 373) and with focal (N = 371), multifocal (N = 33), and diffuse (N = 33) lesions in gut tissues and regional lymph nodes. DNA from peripheral blood samples of these animals was genotyped with the bovine EuroG MD Bead Chip, and the corresponding genotypes were imputed to whole-genome sequencing (WGS) data using the 1000 Bull genomes reference population. A genome-wide association study (GWAS) was performed using the WGS data and the presence or absence of each type of histological lesion in a case–control approach. A total of 192 and 92 single nucleotide polymorphisms (SNPs) defining 13 and 9 distinct quantitative trait loci (QTLs) were highly-associated (P ≤ 5 × 10⁻⁷) with the multifocal (heritability = 0.075) and the diffuse (heritability = 0.189) lesions, respectively. No overlap was seen in the SNPs controlling these distinct pathological outcomes. The identified QTLs overlapped with some QTLs previously associated with PTB susceptibility, bovine tuberculosis susceptibility, clinical mastitis, somatic cell score, bovine respiratory disease susceptibility, tick resistance, IgG level, and length of productive life. Pathway analysis with candidate genes overlapping the identified QTLs revealed a significant enrichment of the keratinization pathway and cholesterol metabolism in the animals with multifocal and diffuse lesions, respectively. To test whether the enrichment of SNP variants in candidate genes involved in the cholesterol metabolism was associated with the diffuse lesions; the levels of total cholesterol were measured in plasma samples of cattle with focal, multifocal, or diffuse lesions or with no visible lesions. Our results showed reduced levels of plasma cholesterol in cattle with diffuse lesions. Taken together, our findings suggested that the variation in MAP-associated pathological outcomes might be, in part, genetically determined and indicative of distinct host responses.

Integrated multi-omics analyses on patient-derived CRC organoids highlight altered molecular pathways in colorectal cancer progression involving PTEN

Background

Colorectal cancer (CRC) represents the fourth leading cause of cancer-related deaths. The heterogeneity of CRC identity limits the usage of cell lines to study this type of tumor because of the limited representation of multiple features of the original malignancy. Patient-derived colon organoids (PDCOs) are a promising 3D-cell model to study tumor identity for personalized medicine, although this approach still lacks detailed characterization regarding molecular stability during culturing conditions. Correlation analysis that considers genomic, transcriptomic, and proteomic data, as well as thawing, timing, and culturing conditions, is missing.

Methods

Through integrated multi–omics strategies, we characterized PDCOs under different growing and timing conditions, to define their ability to recapitulate the original tumor.

Results

Whole Exome Sequencing allowed detecting temporal acquisition of somatic variants, in a patient-specific manner, having deleterious effects on driver genes CRC-associated. Moreover, the targeted NGS approach confirmed that organoids faithfully recapitulated patients’ tumor tissue. Using RNA-seq experiments, we identified 5125 differentially expressed transcripts in tumor versus normal organoids at different time points, in which the PTEN pathway resulted of particular interest, as also confirmed by further phospho-proteomics analysis. Interestingly, we identified the PTEN c.806_817dup (NM_000314) mutation, which has never been reported previously and is predicted to be deleterious according to the American College of Medical Genetics and Genomics (ACMG) classification.

Conclusion

The crosstalk of genomic, transcriptomic and phosphoproteomic data allowed to observe that PDCOs recapitulate, at the molecular level, the tumor of origin, accumulating mutations over time that potentially mimic the evolution of the patient’s tumor, underlining relevant potentialities of this 3D model.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01986-8.

Analysis of mRNA expression differences in bladder cancer metastasis based on TCGA datasets

OBJECTIVE

To investigate the metastatic mechanism of muscle invasive bladder cancer (MIBC), which accounts for approximately 30% of all bladder cancer cases, and is a considerable medical problem with high metastatic and mortality rates.

METHODS

The mRNA levels of patients with metastatic MIBC and nonmetastatic MIBC from The Cancer Genome Atlas dataset were compared. An integrated bioinformatics analysis was performed of the differentially expressed genes (DEGs), and analyses of Gene Ontology, Kyoto Encyclopaedia of Genes and Genomes pathway, protein-protein interaction, and survival were performed to investigate differences between metastatic and nonmetastatic MIBC.

RESULTS

Data from 264 patients were included (131 with, and 133 without, metastasis). A total of 385 significantly DEGs were identified, including 209 upregulated genes and 176 downregulated genes. Based on results using the STRING database and the MCODE plugin of Cytoscape software, two clusters were obtained. Moreover, two genes were identified that may be valuable for prognostic analysis: Keratin 38, type I (KRT38) and Histone cluster 1, H3f (HIST1H3F).

CONCLUSION

The KRT38 and HIST1H3F genes may be important in metastasis of MIBC.

Novel CARMIL2 loss-of-function variants are associated with pediatric inflammatory bowel disease

CARMIL2 is required for CD28-mediated co-stimulation of NF-κB signaling in T cells and its deficiency has been associated with primary immunodeficiency and, recently, very early onset inflammatory bowel disease (IBD). Here we describe the identification of novel biallelic CARMIL2 variants in three patients presenting with pediatric-onset IBD and in one with autoimmune polyendocrine syndrome (APS). None manifested overt clinical signs of immunodeficiency before their diagnosis. The first patient presented with very early onset IBD. His brother was found homozygous for the same CARMIL2 null variant and diagnosed with APS. Two other IBD patients were found homozygous for a nonsense and a missense CARMIL2 variant, respectively, and they both experienced a complicated postoperative course marked by severe infections. Immunostaining of bowel biopsies showed reduced CARMIL2 expression in all the three patients with IBD. Western blot and immunofluorescence of transfected cells revealed an altered expression pattern of the missense variant. Our work expands the genotypic and phenotypic spectrum of CARMIL2 deficiency, which can present with either IBD or APS, aside from classic immunodeficiency manifestations. CARMIL2 should be included in the diagnostic work-up of patients with suspected monogenic IBD.

Keratin intermediate filaments in the colon: guardians of epithelial homeostasis

Keratin intermediate filament proteins are major cytoskeletal components of the mammalian simple layered columnar epithelium in the gastrointestinal tract. Human colon crypt epithelial cells express keratins 18, 19 and 20 as the major type I keratins, and keratin 8 as the type II keratin. Keratin expression patterns vary between species, and mouse colonocytes express keratin 7 as a second type II keratin. Colonic keratin patterns change during cell differentiation, such that K20 increases in the more differentiated crypt cells closer to the central lumen. Keratins provide a structural and mechanical scaffold to support cellular stability, integrity and stress protection in this rapidly regenerating tissue. They participate in central colonocyte processes including barrier function, ion transport, differentiation, proliferation and inflammatory signaling. The cell-specific keratin compositions in different epithelial tissues has allowed for the utilization of keratin-based diagnostic methods. Since the keratin expression pattern in tumors often resembles that in the primary tissue, it can be used to recognize metastases of colonic origin. This review focuses on recent findings on the biological functions of mammalian colon epithelial keratins obtained from pivotal in vivo models. We also discuss the diagnostic value of keratins in chronic colonic disease and known keratin alterations in colon pathologies. This review describes the biochemical properties of keratins and their molecular actions in colonic epithelial cells and highlights diagnostic data in colorectal cancer and inflammatory bowel disease patients, which may facilitate the recognition of disease subtypes and the establishment of personal therapies in the future.

Thymoquinone induces apoptosis and DNA damage in 5-Fluorouracil-resistant colorectal cancer stem/progenitor cells

The high recurrence rates of colorectal cancer have been associated with a small population of cancer stem cells (CSCs) that are resistant to the standard chemotherapeutic drug, 5-fluorouracil (5FU). Thymoquinone (TQ) has shown promising antitumor properties on numerous cancer systems both in vitro and in vivo; however, its effect on colorectal CSCs is poorly established. Here, we investigated TQ's potential to target CSCs in a three-dimensional (3D) sphere-formation assay enriched for a population of colorectal cancer stem/progenitor cells. Our results showed a significant decrease in self-renewal potential of CSC populations enriched from 5FU-sensitive and resistant HCT116 cells at 10-fold lower concentrations when compared to 2D monolayers. TQ decreased the expression levels of colorectal stem cell markers CD44 and Epithelial Cell Adhesion Molecule EpCAM and proliferation marker Ki67 in colonospheres derived from both cell lines and reduced cellular migration and invasion. Further investigation revealed that TQ treatment led to increased TUNEL positivity and a dramatic increase in the amount of the DNA damage marker gamma H2AX particularly in 5FU-resistant colonospheres, suggesting that the diminished sphere forming ability in TQ-treated colonospheres is due to induction of DNA damage and apoptotic cell death. The intraperitoneal injection of TQ in mice inhibited tumor growth of spheres derived from 5FU-sensitive and 5FU-resistant HCT116 cells. Furthermore, TQ induced apoptosis and inhibited NF-κB and MEK signaling in mouse tumors. Altogether, our findings document TQ's effect on colorectal cancer stem-like cells and provide insights into its underlying mechanism of action.

Production and characterization of avian crypt-villus enteroids and the effect of chemicals

BACKGROUND

Three-dimensional models of cell culture such as organoids and mini organs accord better advantage over regular cell culture because of their ability to simulate organ functions hence, used for disease modeling, metabolic research, and the development of therapeutics strategies. However, most advances in this area are limited to mammalian species with little progress in others such as poultry where it can be deployed to study problems of agricultural importance. In the course of enterocyte culture in chicken, we observed that intestinal mucosal villus-crypts self-repair and form spheroid-like structures which appear to be useful as ex vivo models to study enteric physiology and diseases.

RESULTS

The villus-crypts harvested from chicken intestinal mucosa were cultured to generate enteroids, purified by filtration then re cultured with different chemicals and growth factors to assess their response based on their morphological dispositions. Histochemical analyses using marker antibodies and probes showed the enteroids consisting different cell types such as epithelial, goblet, and enteroendocrine cells typical to villi and retain functional characteristics of intestinal mucosa.

CONCLUSIONS

We present a simple procedure to generate avian crypt-villous enteroids containing different cell types. Because the absorptive cells are functionally positioned outwards, similar to the luminal enterocytes, the cells have better advantages to interact with the factors present in the culture medium. Thus, the enteroids have the potential to study the physiology, metabolism, and pathology of the intestinal villi and can be useful for preliminary screenings of the factors that may affect gut health in a cost-effective manner and reduce the use of live animals.

Polyinosinic-polycytidylic acid accelerates intestinal stem cell proliferation via modulating Myc expression

It is well known that exposure of double-stranded RNA (dsRNA) to intestine immediately induces villus damage with severe diarrhea, which is mediated by toll-like receptor 3 signaling activation. However, the role of intestinal stem cells (ISCs) remains obscure during the pathology. In the present study, polyinosinic-polycytidylic acid (poly[I:C]), mimicking viral dsRNA, was used to establish intestinal damage model. Mice were acutely and chronically exposed to poly(I:C), and ISCs in jejunum were analyzed. The results showed that the height of villus was shorter 48 hr after acute poly(I:C) exposure compared with that of controls, while chronic poly(I:C) treatment increased both villus height and crypt depth in jejunum compared with control animals. The numbers of ISCs in jejunum were significantly increased after acute and chronic poly(I:C) exposure. Poly (I:C)-stimulated ISCs have stronger capacities to differentiate into intestine endocrine cells. Mechanistically, poly(I:C) treatment increased expression of Stat1 and Axin2 in the intestinal crypt, which was along with increased expression of Myc, Bcl2, and ISC proliferation. These findings suggest that dsRNA exposure could induce ISC proliferation to ameliorate dsRNA-induced intestinal injury.

Neurotrophic factor GDNF regulates intestinal barrier function in inflammatory bowel disease

Impaired intestinal epithelial barrier (IEB) function with loss of desmosomal junctional protein desmoglein 2 (DSG2) is a hallmark in the pathogenesis of inflammatory bowel disease (IBD). While previous studies have reported that glial cell line-derived neurotrophic factor (GDNF) promotes IEB function, the mechanisms are poorly understood. We hypothesized that GDNF is involved in the loss of DSG2, resulting in impaired IEB function as seen in IBD. In the inflamed intestine of patients with IBD, there was a decrease in GDNF concentrations accompanied by a loss of DSG2, changes of the intermediate filament system, and increased phosphorylation of p38 MAPK and cytokeratins. DSG2-deficient and RET-deficient Caco2 cells revealed that GDNF specifically recruits DSG2 to the cell borders, resulting in increased DSG2-mediated intercellular adhesion via the RET receptor. Challenge of Caco2 cells and enteroids with proinflammatory cytokines as well as dextran sulfate sodium-induced (DSS-induced) colitis in C57Bl/6 mice led to impaired IEB function with reduced DSG2 mediated by p38 MAPK-dependent phosphorylation of cytokeratins. GDNF blocked all inflammation-induced changes in the IEB. GDNF attenuates inflammation-induced impairment of IEB function caused by the loss of DSG2 through p38 MAPK-dependent phosphorylation of cytokeratin. The reduced GDNF in patients with IBD indicates a disease-relevant contribution to the development of IEB dysfunction.

Impact of human milk on the transcriptomic response of fetal intestinal epithelial cells reveals expression changes of immune-related genes

Human milk, the best food for infants, is a dynamic and complex fluid that directly influences the immune system and microbiota establishment.

Human milk, the best food for infants, is a dynamic and complex fluid that directly influences the immune system and microbiota establishment. The protective role of human milk is well known although the mechanisms behind it still need to be uncovered. This study aimed to characterize the impact of human milk in the immature intestine of newborns by analyzing the global transcriptomic response of the FHs 74 int cell line (ATCC CCL-241). The expression of intestinal keratins and other genes with a well-annotated intestinal or epithelial function validated FHs 74 int derived from the fetal small intestine as a model of the intestinal epithelium of newborns. Cells exposed to skimmed human milk showed seventeen differentially expressed genes, most of them up-regulated, including four chemokine genes (CXCL1, CXCL2, CXCL3 and CXCL10) and other immune-related genes. qRT-PCR and ELISA analysis confirmed the microarray data and indicated a different pattern of expression upon milk exposure in FHs 74 int as compared to the adult tumorigenic Caco-2 cell line. The evaluation of the functional significance of these transcriptomic changes reveals that human milk exposure may contribute to the regulation of the inflammatory response in the intestine during the perinatal period, which is characterized by the immaturity of the immune system and a pro-inflammatory phenotype.

Prolonged co-treatment with HGF sustains epithelial integrity and improves pharmacological rescue of Phe508del-CFTR

Cystic fibrosis (CF), the most common inherited disease in Caucasians, is caused by mutations in the CFTR chloride channel, the most frequent of which is Phe508del. Phe508del causes not only intracellular retention and premature degradation of the mutant CFTR protein, but also defective channel gating and decreased half-life when experimentally rescued to the plasma membrane (PM). Despite recent successes in the functional rescue of several CFTR mutations with small-molecule drugs, the folding-corrector/gating-potentiator drug combinations approved for Phe508del-CFTR homozygous patients have shown only modest benefit. Several factors have been shown to contribute to this outcome, including an unexpected intensification of corrector-rescued Phe508del-CFTR PM instability after persistent co-treatment with potentiator drugs. We have previously shown that acute co-treatment with hepatocyte growth factor (HGF) can significantly enhance the chemical correction of Phe508del-CFTR. HGF coaxes the anchoring of rescued channels to the actin cytoskeleton via induction of RAC1 GTPase signalling. Here, we demonstrate that a prolonged, 15-day HGF treatment also significantly improves the functional rescue of Phe508del-CFTR by the VX-809 corrector/VX-770 potentiator combination, in polarized bronchial epithelial monolayers. Importantly, we found that HGF treatment also prevented VX-770-mediated destabilization of rescued Phe508del-CFTR and enabled further potentiation of the rescued channels. Most strikingly, prolonged HGF treatment prevented previously unrecognized epithelial dedifferentiation effects of sustained exposure to VX-809. This was observed in epithelium-like monolayers from both lung and intestinal origin, representing the two systems most affected by adverse symptoms in patients treated with VX-809 or the VX-809/VX-770 combination. Taken together, our findings strongly suggest that co-administration of HGF with corrector/potentiator drugs could be beneficial for CF patients.

HIF stabilization inhibits renal epithelial cell migration and is associated with cytoskeletal alterations

Acute kidney injury (AKI) is a common and potentially lethal complication in the hospitalized patients, with hypoxic injury being as a major cause. The loss of renal tubular epithelial cells (TEC), one of the AKI hallmarks, is potentially followed by tubular regeneration process orchestrated by the remaining uninjured TECs that undergo proliferation and migration. In this study, we used human primary TEC to investigate the initiation of tubular cell migration and associated cytoskeletal alterations in response to pharmacological HIF stabilization which resembles the pathophysiology of hypoxia. Tubular cells have been shown to migrate as cohorts in a wound healing assay. Importantly, cells of distal tubular origin moved faster than those of proximal origin. HIF stabilization impaired TEC migration, which was confirmed by live single cell tracking. HIF stabilization significantly reduced tubular cell migration velocity and promoted cell spreading. In contrast to the control conditions, HIF stabilization induced actin filaments rearrangement and cell adhesion molecules including paxillin and focal adhesion kinase. Condensed bundling of keratin fibers was also observed, while the expression of different types of keratins, phosphorylation of keratin 18, and the microtubule structure were not altered. In summary, HIF stabilization reduced the ability of renal tubular cells to migrate and led to cytoskeleton reorganization. Our data suggested an important involvement of HIF stabilization during the epithelial migration underlying the mechanism of renal regeneration in response to AKI.

Identification of proteins with the CDw75 epitope in human colorectal cancer

The CDw75 epitope is an α(2,6) sialylated antigen overexpressed in colorectal cancer (CRC), where its expression correlates with the progression of the disease. The CDw75 epitope is located mainly in N-glycoproteins, whose identity remains unknown. The aim of the present study was to identify proteins with the CDw75 epitope as a strategy to deepen the understanding of molecular pathogenesis of CRC and to identify novel biomarkers for this disease. For this purpose, a two-dimensional electrophoresis approach was employed. Protein spots in the gels were matched to the corresponding CDw75 positive spots in the immunoblotted polyvinylidene difluoride membranes, and further identification of the protein species was performed by mass spectrometry. Additionally, one-dimensional western blotting experiments were performed to verify the expression of these candidate proteins in the colorectal tissue and their coincidence in molecular mass with the CDw75-positive bands. The findings of the present study indicate that haptoglobin and the keratins 8 (K8) and 18 (K18) are proteins with the CDw75 epitope in the colorectal tissue from CRC patients and also suggest novel functions and cellular locations for these proteins in the colorectal tissue and in relation to CRC.

Biopsy-derived Intestinal Epithelial Cell Cultures for Pathway-based Stratification of Patients With Inflammatory Bowel Disease

BACKGROUND

Endoplasmic reticulum [ER] stress was shown to be pivotal in the pathogenesis of inflammatory bowel disease. Despite progress in inflammatory bowel disease [IBD] drug development, not more than one-third of patients achieve steroid-free remission and mucosal healing with current therapies. Furthermore, patient stratification tools for therapy selection are lacking. We aimed to identify and quantify epithelial ER stress in a patient-specific manner in an attempt towards personalised therapy.

METHODS

A biopsy-derived intestinal epithelial cell culture system was developed and characterised. ER stress was induced by thapsigargin and quantified with a BiP enzyme-linked immunosorbent assay [ELISA] of cell lysates from 35 patients with known genotypes, who were grouped based on the number of IBD-associated ER stress and autophagy risk alleles.

RESULTS

The epithelial character of the cells was confirmed by E-cadherin, ZO-1, and MUC2 staining and CK-18, CK-20, and LGR5 gene expression. Patients with three risk alleles had higher median epithelial BiP-induction [vs untreated] levels compared with patients with one or two risk alleles [p = 0.026 and 0.043, respectively]. When autophagy risk alleles were included and patients were stratified in genetic risk quartiles, patients in Q2, Q3, and Q4 had significantly higher ER stress [BiP] when compared with Q1 [p = 0.034, 0.040, and 0.034, respectively].

CONCLUSIONS

We developed and validated an ex vivo intestinal epithelial cell culture system and showed that patients with more ER stress and autophagy risk alleles have augmented epithelial ER stress responses. We thus presented a personalised approach whereby patient-specific defects can be identified, which in turn could help in selecting tailored therapies.

Comparative proteomic analysis of rats subjected to water immersion and restraint stress as an insight into gastric ulcers

In the present study, comparative proteomic analysis was performed in rats subjected to water immersion-restraint stress (WRS). A total of 26 proteins were differentially expressed and identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry. Among the 26 differentially expressed protein spots identified, 13 proteins were significantly upregulated under WRS, including pyruvate kinase and calreticulin, which may be closely associated with energy metabolism. In addition, 12 proteins were downregulated under WRS, including hemoglobin subunit β-2 and keratin type II cytoskeletal 8, which may be important in protein metabolism and cell death. Gene Ontology analysis revealed the cellular distribution, molecular function and biological processes of the identified proteins. The mRNA levels of certain differentially expressed proteins were analyzed using fluorescence quantitative polymerase chain reaction analysis. The results of the present study aimed to offer insights into proteins, which are differentially expressed in gastric ulcers in stress, and provide theoretical evidence of a radical cure for gastric ulcers in humans.

Skin Mucus of Gilthead Sea Bream (Sparus aurata L.). Protein Mapping and Regulation in Chronically Stressed Fish

The skin mucus of gilthead sea bream was mapped by one-dimensional gel electrophoresis followed by liquid chromatography coupled to high resolution mass spectrometry using a quadrupole time-of-flight mass analyzer. More than 2,000 proteins were identified with a protein score filter of 30. The identified proteins were represented in 418 canonical pathways of the Ingenuity Pathway software. After filtering by canonical pathway overlapping, the retained proteins were clustered in three groups. The mitochondrial cluster contained 59 proteins related to oxidative phosphorylation and mitochondrial dysfunction. The second cluster contained 79 proteins related to antigen presentation and protein ubiquitination pathways. The third cluster contained 257 proteins where proteins related to protein synthesis, cellular assembly, and epithelial integrity were over-represented. The latter group also included acute phase response signaling. In parallel, two-dimensional gel electrophoresis methodology identified six proteins spots of different protein abundance when comparing unstressed fish with chronically stressed fish in an experimental model that mimicked daily farming activities. The major changes were associated with a higher abundance of cytokeratin 8 in the skin mucus proteome of stressed fish, which was confirmed by immunoblotting. Thus, the increased abundance of markers of skin epithelial turnover results in a promising indicator of chronic stress in fish.

Novel mouse model recapitulates genome and transcriptome alterations in human colorectal carcinomas

Human colorectal carcinomas are defined by a nonrandom distribution of genomic imbalances that are characteristic for this disease. Often, these imbalances affect entire chromosomes. Understanding the role of these aneuploidies for carcinogenesis is of utmost importance. Currently, established transgenic mice do not recapitulate the pathognonomic genome aberration profile of human colorectal carcinomas. We have developed a novel model based on the spontaneous transformation of murine colon epithelial cells. During this process, cells progress through stages of pre-immortalization, immortalization and, finally, transformation, and result in tumors when injected into immunocompromised mice. We analyzed our model for genome and transcriptome alterations using ArrayCGH, spectral karyotyping (SKY), and array based gene expression profiling. ArrayCGH revealed a recurrent pattern of genomic imbalances. These results were confirmed by SKY. Comparing these imbalances with orthologous maps of human chromosomes revealed a remarkable overlap. We observed focal deletions of the tumor suppressor genes Trp53 and Cdkn2a/p16. High-level focal genomic amplification included the locus harboring the oncogene Mdm2, which was confirmed by FISH in the form of double minute chromosomes. Array-based global gene expression revealed distinct differences between the sequential steps of spontaneous transformation. Gene expression changes showed significant similarities with human colorectal carcinomas. Pathways most prominently affected included genes involved in chromosomal instability and in epithelial to mesenchymal transition. Our novel mouse model therefore recapitulates the most prominent genome and transcriptome alterations in human colorectal cancer, and might serve as a valuable tool for understanding the dynamic process of tumorigenesis, and for preclinical drug testing. © 2016 Wiley Periodicals, Inc.

Keratins Are Altered in Intestinal Disease-Related Stress Responses

Keratin (K) intermediate filaments can be divided into type I/type II proteins, which form obligate heteropolymers. Epithelial cells express type I-type II keratin pairs, and K7, K8 (type II) and K18, K19 and K20 (type I) are the primary keratins found in the single-layered intestinal epithelium. Keratins are upregulated during stress in liver, pancreas, lung, kidney and skin, however, little is known about their dynamics in the intestinal stress response. Here, keratin mRNA, protein and phosphorylation levels were studied in response to murine colonic stresses modeling human conditions, and in colorectal cancer HT29 cells. Dextran sulphate sodium (DSS)-colitis was used as a model for intestinal inflammatory stress, which elicited a strong upregulation and widened crypt distribution of K7 and K20. K8 levels were slightly downregulated in acute DSS, while stress-responsive K8 serine-74 phosphorylation (K8 pS74) was increased. By eliminating colonic microflora using antibiotics, K8 pS74 in proliferating cells was significantly increased, together with an upregulation of K8 and K19. In the aging mouse colon, most colonic keratins were upregulated. In vitro, K8, K19 and K8 pS74 levels were increased in response to lipopolysaccharide (LPS)-induced inflammation in HT29 cells. In conclusion, intestinal keratins are differentially and dynamically upregulated and post-translationally modified during stress and recovery.

Intermediate Filaments and Polarization in the Intestinal Epithelium

The cytoplasmic intermediate filament cytoskeleton provides a tissue-specific three-dimensional scaffolding with unique context-dependent organizational features. This is particularly apparent in the intestinal epithelium, in which the intermediate filament network is localized below the apical terminal web region and is anchored to the apical junction complex. This arrangement is conserved from the nematode Caenorhabditis elegans to humans. The review summarizes compositional, morphological and functional features of the polarized intermediate filament cytoskeleton in intestinal cells of nematodes and mammals. We emphasize the cross talk of intermediate filaments with the actin- and tubulin-based cytoskeleton. Possible links of the intermediate filament system to the distribution of apical membrane proteins and the cell polarity complex are highlighted. Finally, we discuss how these properties relate to the establishment and maintenance of polarity in the intestine.

Spontaneous and transgenic rodent models of inflammatory bowel disease

Inflammatory Bowel Disease (IBD) is a multifactorial disorder with many different putative influences mediating disease onset, severity, progression and diminution. Spontaneous natural IBD is classically expressed as Crohn's Disease (CD) and Ulcerative Colitis (UC) commonly found in primates; lymphoplasmocytic enteritis, eosinophilic gastritis and colitis, and ulcerative colitis with neuronal hyperplasia in dogs; and colitis in horses. Spontaneous inflammatory bowel disease has been noted in a number of rodent models which differ in genetic strain background, induced mutation, microbiota influences and immunopathogenic pathways. Histological lesions in Crohn's Disease feature noncaseating granulomatous inflammation while UC lesions typically exhibit ulceration, lamina propria inflammatory infiltrates and lack of granuloma development. Intestinal inflammation caused by CD and UC is also associated with increased incidence of intestinal neoplasia. Transgenic murine models have determined underlying etiological influences and appropriate therapeutic targets in IBD. This literature review will discuss current opinion and findings in spontaneous IBD, highlight selected transgenic rodent models of IBD and discuss their respective pathogenic mechanisms. It is very important to provide accommodation of induced putative deficits in activities of daily living and to assess discomfort and pain levels in the face of significant morbidity and/or mortality in these models. Epigenetic, environmental (microbiome, metabolome) and nutritional factors are important in IBD pathogenesis, and evaluating ways in which they influence disease expression represent potential investigative approaches with the greatest potential for new discoveries.

Current approaches to the diagnosis and treatment of white sponge nevus

White sponge nevus (WSN) in the oral mucosa is a rare autosomal dominant genetic disease. The involved mucosa is white or greyish, thickened, folded and spongy. The genes associated with WSN include mutant cytokeratin keratin 4 (KRT4) and keratin 13 (KRT13). In recent years, new cases of WSN and associated mutations have been reported. Here, we summarise the recent progress in our understanding of WSN, including clinical reports, genetics, animal models, treatment, pathogenic mechanisms and future directions. Gene-based diagnosis and gene therapy for WSN may become available in the near future and could provide a reference and instruction for treating other KRT-associated diseases.

The amount of keratins matters for stress protection of the colonic epithelium

Keratins (K) are important for epithelial stress protection as evidenced by keratin mutations predisposing to human liver diseases and possibly inflammatory bowel diseases. A role for K8 in the colon is supported by the ulcerative colitis-phenotype with epithelial hyperproliferation and abnormal ion transport in K8-knockout (K8-/-) mice. The heterozygote knockout (K8+/-) colon appears normal but displays a partial ion transport-defect. Characterizing the colonic phenotype we show that K8+/- colon expresses ~50% less keratins compared to K8 wild type (K8+/+) but de novo K7 expression is observed in the top-most cells of the K8+/- and K8-/- crypts. The K8+/- colonic crypts are significantly longer due to increased epithelial hyperproliferation, but display no defects in apoptosis or inflammation in contrast to K8-/-. When exposed to colitis using the dextran sulphate sodium-model, K8+/- mice showed higher disease sensitivity and delayed recovery compared to K8+/+ littermates. Therefore, the K8+/- mild colonic phenotype correlates with decreased keratin levels and increased sensitivity to experimental colitis, suggesting that a sufficient amount of keratin is needed for efficient stress protection in the colonic epithelia.

Inflammation decreases keratin level in ulcerative colitis; inadequate restoration associates with increased risk of colitis-associated cancer

Background

Keratins are intermediate filament (IF) proteins, which form part of the epithelial cytoskeleton and which have been implicated pathology of inflammatory bowel diseases (IBD).

Methods

In this study biopsies were obtained from IBD patients grouped by disease duration and subtype into eight categories based on cancer risk and inflammatory status: quiescent recent onset (<5 years) UC (ROUC); UC with primary sclerosing cholangitis; quiescent long-standing pancolitis (20–40 years) (LSPC); active colitis and non-inflamed proximal colonic mucosa; pancolitis with dysplasia-both dysplastic lesions (DT) and distal rectal mucosa (DR); control group without pathology. Alterations in IF protein composition across the groups were determined by quantitative proteomics. Key protein changes were validated by western immunoblotting and immunohistochemical analysis.

Result

Acute inflammation resulted in reduced K8, K18, K19 and VIM (all p<0.05) compared to controls and non inflamed mucosa; reduced levels of if– associated proteins were also seen in DT and DR. Increased levels of keratins in LSPC was noted relative to controls or ROUC (K8, K18, K19 and VIM, p<0.05). Multiple K8 forms were noted on immunoblotting, with K8 phosphorylation reduced in progressive disease along with an increase in VIM:K8 ratio. K8 levels and phosphorylation are reduced in acute inflammation but appear restored or elevated in subjects with clinical and endoscopic remission (LSPC) but not apparent in subjects with elevated risk of cancer.

Conclusions

These data suggest that keratin regulation in remission may influence subsequent cancer risk.

Reduced keratin expression in colorectal neoplasia and associated fields is reversible by diet and resection

BACKGROUND

Patients with adenomatous colonic polyps are at increased risk of developing further polyps suggesting field-wide alterations in cancer predisposition. The current study aimed to identify molecular alterations in the normal mucosa in the proximity of adenomatous polyps and to assess the modulating effect of butyrate, a chemopreventive compound produced by fermentation of dietary residues.

METHODS

A cross-sectional study was undertaken in patients with adenomatous polyps: biopsy samples were taken from the adenoma, and from macroscopically normal mucosa on the contralateral wall to the adenoma and from the mid-sigmoid colon. In normal subjects biopsies were taken from the mid-sigmoid colon. Biopsies were frozen for proteomic analysis or formalin-fixed for immunohistochemistry. Proteomic analysis was undertaken using iTRAQ workflows followed by bioinformatics analyses. A second dietary fibre intervention study arm used the same endpoints and sampling strategy at the beginning and end of a high-fibre intervention.

RESULTS

Key findings were that keratins 8, 18 and 19 were reduced in expression level with progressive proximity to the lesion. Lesional tissue exhibited multiple K8 immunoreactive bands and overall reduced levels of keratin. Biopsies from normal subjects with low faecal butyrate also showed depressed keratin expression. Resection of the lesion and elevation of dietary fibre intake both appeared to restore keratin expression level.

CONCLUSION

Changes in keratin expression associate with progression towards neoplasia, but remain modifiable risk factors. Dietary strategies may improve secondary chemoprevention.

TRIAL REGISTRATION NUMBER

ISRCTN90852168.

Intestinal cell barrier function in vitro is severely compromised by keratin 8 and 18 mutations identified in patients with inflammatory bowel disease

Keratin 8 and 18 (K8/K18) mutations have been implicated in the aetiology of certain pathogenic processes of the liver and pancreas. While some K8 mutations (K8 G62C, K8 K464N) are also presumed susceptibility factors for inflammatory bowel disease (IBD), the only K18 mutation (K18 S230T) discovered so far in an IBD patient is thought to be a polymorphism. The aim of our study was to demonstrate that these mutations might also directly affect intestinal cell barrier function. Cell monolayers of genetically engineered human colonocytes expressing these mutations were tested for permeability, growth rate and resistance to heat-stress. We also calculated the change in dissociation constant (K_d, measure of affinity) each of these mutations introduces into the keratin protein, and present the first model of a keratin dimer L12 region with in silico clues to how the K18 S230T mutation may affect keratin function. Physiologically, these mutations cause up to 30% increase in paracellular permeability in vitro. Heat-stress induces little keratin clumping but instead cell monolayers peel off the surface suggesting a problem with cell junctions. K18 S230T has pronounced pathological effects in vitro marked by high K_d, low growth rate and increased permeability. The latter may be due to the altered distribution of tight junction components claudin-4 and ZO-1. This is the first time intestinal cells have been suggested also functionally impaired by K8/K18 mutations. Although an in vitro colonocyte model system does not completely mimic the epithelial lining of the intestine, nevertheless the data suggest that K8/K18 mutations may be also able to produce a phenotype in vivo.

Keratin 13 mutations associated with oral white sponge nevus in two Chinese families

White sponge nevus (WSN) is an autosomal dominant hereditary disease. Keratin 4 (KRT4) and Keratin 13 (KRT13) gene mutations were involved in the WSN. We recruited two WSN Chinese families, and oral lesion biopsy with hematoxylin and eosin staining showed that patients had significant pathological characteristics. The mutations of KRT4 and KRT13 gene were detected by PCR and direct sequencing. The multiple alignments of KRT13 from 23 diverse species homology analyses were performed by the ClustalW program. The KRT13 expression was measured by Real-Time RT-PCR and Western blot analysis. Sequencing analysis revealed two mutations of KRT13 gene: one mutation was 332T>C and amino acid change was Leu111Pro. Another mutation was 340C>T and amino acid change was Arg114Cys. The sequence of KRT13 was highly conserved. Real-Time RT-PCR and Western blot analysis results show that KRT13 expression level is lower in patient but keep almost no change in mRNA level. When cells were treated with MG132, KRT13 protein level was increased and kept almost the same in normal and patient cells. We identified two heritable mutations in the KRT13 gene, which were associated with the development of WSN. The abnormal degradation of KRT13 protein of WSN may probably associate with the abnormal ubiquitination process.

Serum m 30 levels reflects ulcerative colitis activity

BACKGROUND

Apoptosis plays a role in epithelial and mucosal injury, which is 1 of the mechanisms in the pathogenesis of ulcerative colitis. Apoptotic cells increase as a result of injured mucosa in ulcerative colitis and serum M 30 levels increase in epithelial cell apoptosis. In this study, we aimed to evaluate the relation between M 30 serum levels and ulcerative colitis activity.

METHODS

Eighty patients with ulcerative colitis and 40 healthy controls were enrolled into the study. The patient group consisted of 31 extensive colitis, 30 left-sided colitis, and 19 proctitis. The activity of ulcerative colitis was determined with clinical and endoscopic findings. Serum M 30 levels, acute phase reactants, and biochemical tests were analyzed in all subjects.

RESULTS

Serum M 30 levels in patients with active ulcerative colitis were significantly higher when compared with the healthy controls (165.6 ± 60.6 and 129.6 ± 37.4; P = 0.003). Serum M 30 levels in active left-sided colitis patients was significantly higher when compared with patients in remission phase (180.6 ± 58.5, 141.5 ± 35.4; P = 0.044). When we exclude patients with ulcerative proctitis, M 30 levels in active ulcerative colitis patients were significantly higher than that the patients in remission phase (174.0 ± 63.5, 135.0 ± 29.9; P = 0.017).

CONCLUSIONS

We found that M 30 levels increase in patients with active ulcerative colitis. Our findings support the role of apoptosis demonstrated by serum M 30 levels in the pathogenesis of active ulcerative colitis.

Parkin induces upregulation of 40S ribosomal protein SA and posttranslational modification of cytokeratins 8 and 18 in human cervical cancer cells

Parkin was originally identified as a protein associated with Parkinson's disease. Recently, numerous research studies have suggested that parkin acts as a tumor suppressor. In accordance with these studies, we previously reported that overexpression of parkin in HeLa cells induced growth inhibition. To elucidate possible mechanisms by which parkin may inhibit cell growth, HeLa cells were infected with adenoviruses expressing either the parkin gene or adenovirus alone for 72 h and a total proteomic analysis was performed using 2-D gel electrophoresis followed by LC-MS/MS. We identified three proteins whose expression changed between the two groups: the 40S ribosomal protein SA (RPSA) was downregulated in parkin virus-infected cells, and cytokeratins 8 and 18 exhibited an acid shift in pI value without a change in molecular weight, suggesting that these proteins became phosphorylated in parkin virus-infected cells. The changes in these three proteins were first observed at 60 h postinfection and were most dramatic at 72 h postinfection. Because upregulation of RPSA and dephosphorylation of cytokeratins 8/18 have been linked with tumor progression, these data suggest that parkin may inhibit cell growth, at least in part, by decreasing RPSA expression and inducing phosphorylation of cytokeratin 8/18.