Down-regulation of collagen I biosynthesis in intestinal epithelial cells exposed to indomethacin: a comparative proteome analysis

Identification of COL3A1 as a candidate protein involved in the crosstalk between obesity and diarrhea using quantitative proteomics and machine learning

BACKGROUND

Increasing epidemiologic studies have shown a positive correlation between obesity and chronic diarrhea. Nevertheless, the precise etiology remains uncertain.

METHODS

We performed a comprehensive proteomics analysis utilizing the data-independent acquisition (DIA) technique on jejunal tissues from patients with obesity and chronic diarrhea (OD, n = 33), obese patients (OB, n = 10), and healthy controls (n = 8). Differentially expressed proteins (DEPs) in OD vs. control and OD vs. OB comparisons were subjected to pathway enrichment and protein-protein interaction (PPI) network analysis. Machine learning algorithms were adopted on overlapping DEPs in both comparisons. The candidate protein was further validated using Western blot, immunohistochemistry (IHC), and in vitro experiments.

RESULTS

We identified 189 and 228 DEPs in OD vs. control and OD vs. OB comparisons, respectively. DEPs in both comparisons were co-enriched in extracellular matrix (ECM) organization. Downregulated DEPs were associated with tight junction and ECM-receptor interaction in OD vs. control and OD vs. OB comparisons, respectively. Machine learning algorithms selected 3 proteins from 14 overlapping DEPs in both comparisons, among which collagen alpha-1(III) chain (COL3A1) was identified as a core protein in PPI networks. Western blot and IHC verified the expression of COL3A1. Moreover, the tight junction-related proteins decreased after the knockdown of COL3A1 in Caco2 intestinal cells upon PA challenge, consistent with the proteomics results.

CONCLUSIONS

We generated in-depth profiling of a proteomic dataset from samples of OD patients and provided unique insights into disease pathogenesis. COL3A1 was involved in the crosstalk between obesity and intestinal homeostasis via the ECM-receptor interaction pathway.

Yersinia enterocolitica and Lactobacillus fermentum induces differential cellular and behavioral responses during diclofenac biotransformation in rat gut

Non-steroidal anti-inflammatory drugs (NSAIDs) can induce small-intestinal injuries through inhibition of prostaglandin synthesis. Gut has an important role in building and maintaining the barriers to avoid the luminal gut microbiota from invading the host, and cytoskeleton plays a crucial role in the maintenance of cellular barrier. The recent advances suggest a bi-directional interaction between the drugs and gut microbiota, where gut microbes can metabolize the drugs, and in response drugs can alter the composition of gut microbiota. In the present study, we evaluated the effect of diclofenac on rat gut, when co-administrated with either Yersinia enterocolitica strain 8081 (an enteropathogen) or Lactobacillus fermentum strain 9338 (a probiotic). The LC-MS/MS based label-free quantitation of rat gut proteins revealed 51.38% up-regulated, 48.62% down-regulated in diclofenac-Y. enterocolitica strain 8081 (D*Y), and 74.31% up-regulated, 25.69% down-regulated in diclofenac-L. fermentum strain 9338 (D*L) experiments. The identified proteins belonged to cytoskeleton, metabolism, heme biosynthesis and binding, stress response, apoptosis and redox homeostasis, immune and inflammatory response, and detoxification and antioxidant defence. Further, the histopathological and biochemical analysis indicated more pronounced histological alterations and oxidative stress (enhanced malonaldehyde and altered antioxidant levels) in D*Y rats than D*L rats, compared to control rats. Elevated plus maze (EPM) test performed to determine the behavioral changes, suggested increased anxiety in D*Y rats than D*L rats, compared to control rats. These results together suggest the differential role of either bacterium in biotransformation of diclofenac, and inflammatory and cellular redox response.

The vitamin D receptor Taq I polymorphism is associated with reduced VDR and increased PDIA3 protein levels in human intestinal fibroblasts

The synonymous single nucleotide polymorphism (SNP) rs731236, located in the vitamin D receptor (VDR) gene (Taq I) has been associated with both decreased levels of the protein in peripheral blood mononuclear cells and a fibrosis-related complication in Crohn´s disease (CD). Interactions between VDR and a protein-disulfide isomerase-associated 3 (PDIA3) in the regulation of extracellular matrix have been reported and we aim to analyze the relevance of the VDR genotypes and the effects of Vitamin D (VD) in the expression of VDR, PDIA3 and proliferation of intestinal fibroblasts. Human intestinal fibroblasts were isolated from the non-affected surgical resections of colorectal patients and classified according to the VDR genotype. In some cases, cells were transfected with specific PDIA3 siRNA. Basal and VD-stimulated expression of VDR, PDIA3 and Collagen 1A1 (COL1A1) as well as fibroblast migration/proliferation were analyzed. Our data show that intestinal fibroblasts homozygous for the C allele in the VDR gene exhibited lower VDR protein levels and higher proliferation than cells homozygous for the T allele. VD increased VDR and attenuated the accelerated proliferation of CC fibroblasts. The diminished VDR level detected in CC cells was associated with increased levels of both PDIA3 and COL1A1 expression and the transient silencing of PDIA3 significantly reduced COL1A1 expression. We conclude that intestinal fibroblasts homozygous for the C allele in the VDR gene exhibited: reduced VDR protein levels, increased proliferation and increased PDIA3/COL1A1 expression. Treatment with VD increased VDR and attenuated proliferation of these cells.

Current Topics of Strategy of NSAID-Induced Small Intestinal Lesions

Small intestinal mucosal injuries have been recently recognized as common complications associated with non-steroidal anti-inflammatory drugs (NSAIDs) because video capsule endoscopy and balloon enteroscopy are now available for the detection of small intestinal lesions. Small intestinal injury occurs not in an acid-dependent mechanism but by various factors such as enteric bacteria, bile acids, prostaglandin (PG) deficiency and topical factors (abnormal intestinal mucosal permeability, mitochondrial dysfunction, reactive oxygen species, endoplasmic reticulum stress and so on), and there is no well-established prophylactic approach. Several experimental and clinical studies found the effectiveness of some of the mucoprotective drugs, PG analogs, but not that of acid suppressants. Considering the effect of proton pump inhibitors (PPIs) for upper gastrointestinal (GI) disease and in the small intestine, the following 2 kinds of strategies against NSAID-induced GI injuries may be recommended. In patients with a high risk of upper GI disease (peptic ulcer etc.), simultaneous administration of a PPI (for upper GI disease) and a mucoprotective drug (for small intestine) is needed to prevent NSAID-induced GI injury. In other cases, an effective mucoprotective drug is enough for the protection of the entire digestive tract, that is, starting from the esophagus to the small intestine. These strategies may fulfill both economical and curative effects.

Effect of prophylactic indomethacin administration and early feeding on spontaneous intestinal perforation in extremely low-birth-weight infants

OBJECTIVE

To determine the effect of concomitant administration of prophylactic indomethacin and early enteral feeds on the risk of spontaneous intestinal perforation (SIP) in extremely low-birth-weight (ELBW) infants, and to describe the variation in prophylactic indomethacin use in Canada.

STUDY DESIGN

A retrospective cohort study of 4268 ELBW infants born at <30 weeks' gestation admitted to Canadian neonatal units between 2010 and 2014 was conducted. Prophylactic indomethacin (I+ or I-, administered within 24 h) and early feeding (E+ or E-, initiated in the first 2 days) exposures were studied concurrently and independently. The primary outcomes were SIP and death before discharge. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

Compared with the I-/E+ reference group (n=1829), infants in I+/E+ (n=285; aOR 2.92, 95% CI 1.41 to 6.08) and I+/E- (n=213; aOR 2.84, 95% CI 1.35 to 5.98) groups had higher odds of SIP, whereas those in the I-/E- group had similar odds (n=1941; aOR 1.37, 95% CI 0.88 to 2.14). Odds of SIP were higher in the indomethacin exposed group (I+) compared with the unexposed (I-) group when controlled for early feeding (aOR 2.43, 95% CI 1.41 to 4.19), but not in the early feeding group when controlled for indomethacin. The use of prophylactic indomethacin ranged from 0% usage in 13 sites to 78% use in one site.

CONCLUSION

Prophylactic indomethacin was associated with increased odds of SIP independently from early feeding in this cohort; however, early enteral feeding was not associated with SIP. Marked variation in the use of prophylactic indomethacin was identified.

Arabinoxylan hydrolyzates as immunomodulators in lipopolysaccharide-induced RAW264.7 macrophages

The immunomodulatory effects of arabinoxylan (AX) have been demonstrated before. However, these effects could be structure driven. Thus, we indicate the relationship between fine structural details and immunomodulatory properties of AX.

NSAID-induced small intestinal damage--roles of various pathogenic factors

BACKGROUND/AIMS

NSAID-induced enteropathy has been the focus of recent basic and clinical research subsequent to the development of the capsule endoscope and double-balloon endoscope. We review the possible pathogenic mechanisms underlying NSAID-induced enteropathy and discuss the role of the inhibition of COX-1/COX-2 and the influences of food as well as various prophylactic treatments on these lesions.

METHODS

Studies were performed in experimental animals.

RESULTS

Multiple factors, such as intestinal hypermotility, decreased mucus secretion, enterobacteria, and upregulation of iNOS/NO expression, are involved in the pathogenesis of NSAID-induced enteropathy, in addition to the decreased production of PGs due to the inhibition of COX. Enterobacterial invasion is the most important pathogenic event, and intestinal hypermotility, which was associated with this event, is essential for the development of these lesions. NSAIDs also upregulate the expression of COX-2, and the inhibition of both COX-1 and COX-2 is required for the intestinal ulcerogenic properties of NSAIDs to manifest. NSAID-induced enteropathy is prevented by PGE2, atropine, ampicillin, and aminoguanidine as well as soluble dietary fiber, and exacerbated by antisecretory drugs such as proton pump inhibitors.

CONCLUSION

These findings on the pathogenesis of NSAID-induced enteropathy will be useful for the future development of intestinal-sparing alternatives to standard NSAIDs.

Molecular Cloning, Characterization, and Expression Analysis of a Prolyl 4-Hydroxylase from the Marine Sponge Chondrosia reniformis

Prolyl 4-hydroxylase (P4H) catalyzes the hydroxylation of proline residues in collagen. P4H has two functional subunits, α and β. Here, we report the cDNA cloning, characterization, and expression analysis of the α and β subunits of the P4H derived from the marine sponge Chondrosia reniformis. The amino acid sequence of the α subunit is 533 residues long with an M r of 59.14 kDa, while the β subunit counts 526 residues with an M r of 58.75 kDa. Phylogenetic analyses showed that αP4H and βP4H are more related to the mammalian sequences than to known invertebrate P4Hs. Western blot analysis of sponge lysate protein cross-linking revealed a band of 240 kDa corresponding to an α2β2 tetramer structure. This result suggests that P4H from marine sponges shares the same quaternary structure with vertebrate homologous enzymes. Gene expression analyses showed that αP4H transcript is higher in the choanosome than in the ectosome, while the study of factors affecting its expression in sponge fragmorphs revealed that soluble silicates had no effect on the αP4H levels, whereas ascorbic acid strongly upregulated the αP4H mRNA. Finally, treatment with two different tumor necrosis factor (TNF)-alpha inhibitors determined a significant downregulation of αP4H gene expression in fragmorphs demonstrating, for the first time in Porifera, a positive involvement of TNF in sponge matrix biosynthesis. The molecular characterization of P4H genes involved in collagen hydroxylation, including the mechanisms that regulate their expression, is a key step for future recombinant sponge collagen production and may be pivotal to understand pathological mechanisms related to extracellular matrix deposition in higher organisms.