Organisms from all domains of life depend on filaments of the protein actin to provide structure and to support internal movements. Many eukaryotic cells use forces produced by actin polymerization for their motility, and myosin motor proteins use ATP hydrolysis to produce force on actin filaments. Actin polymerizes spontaneously, followed by hydrolysis of a bound adenosine triphosphate (ATP). Dissociation of the γ-phosphate prepares the polymer for disassembly. This review provides an overview of the properties of actin and shows how dozens of proteins control both the assembly and disassembly of actin filaments. These players catalyze nucleotide exchange on actin monomers, initiate polymerization, promote phosphate dissociation, cap the ends of polymers, cross-link filaments to each other and other cellular components, and sever filaments.

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Actin and Actin-Binding Proteins

IBS is one of the most common functional gastrointestinal disorders worldwide and is thought to be the result of disturbed neural function along the brain-gut axis. The mechanisms behind this disturbance are not clear, but important roles for low-grade inflammation and immunological alterations in the development of symptoms compatible with IBS have become evident. The development of long-standing gastrointestinal symptoms after infectious gastroenteritis and patients with IBD in remission frequently having functional gastrointestinal symptoms support this hypothesis. An increased innate immune activity in the intestinal mucosa and in blood is found in subpopulations of patients with IBS. Mast cells and monocytes seem to be particularly important. In addition, studies have demonstrated that IBS may be associated with an activated adaptive immune response. Increased epithelial barrier permeability and an abnormal gut flora might lead to increased activation of the intestinal immune system. Functional and anatomical evidence for abnormal neuroimmune interactions has been found in patients with IBS. The link between immune alterations and severity of gastrointestinal symptoms and the positive effect of anti-inflammatory treatments in IBS further highlight the relevance of neuroimmune interactions in this condition.

Pathogenesis of IBS: role of inflammation, immunity and neuroimmune interactions

Recent advances in apoptosis, mitochondria and drug resistance in cancer cells.

Irritable bowel syndrome (IBS) has been associated with high prevalence of psychological disorders. However, it remains unclear whether IBS and each of its subtypes (predominant diarrhea IBS-D, constipation IBS-C, mixed IBS-M) are associated with higher anxiety and depressive symptoms levels. This study aimed to determine the associations of IBS and each of its subtypes with anxiety and/or depression. We conducted a systematic review and meta-analysis using five electronic databases (PubMed, PsychINFO, BIOSIS, Science Direct, and Cochrane CENTRAL). We selected case–control studies comparing anxiety and depression levels of patients with IBS to healthy controls, using standardized rating scales. Outcomes were measured as random pooled standardized mean differences (SMD). Ten studies were included in our analysis (885 patients and 1,384 healthy controls). Patients with IBS had significant higher anxiety and depression levels than controls (respectively, SMD = 0.76, 95 % CI 0.47; 0.69, p < 0.01, I2 = 81.7 % and SMD = 0.80, 95 % CI 0.42; 1.19, p < 0.01, I2 = 90.7 %). This significant difference was confirmed for patients with IBS-C and -D subtypes for anxiety, and only in IBS-D patients for depression. However, other IBS subtypes had a statistical trend to be associated with both anxiety and depressive symptomatology, which suggests a lack of power due to the small number of studies included. Patients with IBS had significantly higher levels of anxiety and depression than healthy controls. Anxiety and depression symptomatology should be systematically checked and treated in IBS patients, as psychological factors are important moderators of symptom severity, symptom persistence, decisions to seek treatment, and response to treatment.

Anxiety and depression comorbidities in irritable bowel syndrome (IBS): a systematic review and meta-analysis.

Edible ginger-derived nanoparticles: A novel therapeutic approach for the prevention and treatment of inflammatory bowel disease and colitis-associated cancer.

Background/Aims: Psychological factors and subtle histopathological changes have been implicated in irritable bowel syndrome (IBS). The aims of the present study were to investigate whether the numbers of enterochromaffin (EC) cells, mast cells, and lamina propria T lymphocytes are altered in IBS, and evaluate the relationship of such alterations with psychological factors.

Methods:  Forty-two consecutive IBS patients (M : F = 17:25, mean age 48 years) fulfilling the Rome III criteria and twelve asymptomatic healthy controls underwent rectal biopsy. Immunostaining was performed for EC cells, mast cells, and lamina propria T lymphocytes.

Results:  The IBS group included five post-infectious (PI) IBS and 37 non-PI IBS patients. Significantly more EC cells, mast cells and lamina propria T lymphocytes were observed in PI IBS patients. Mast cells significantly increased in non-PI IBS-D (diarrhea) patients, but not in non-PI IBS-C (constipation) and non-PI IBS-M (mixed) patients. Enterochromaffin cell numbers were not significantly altered in non-PI IBS patients. Anxiety and depression scores did not differ between IBS patients with and without abnormal increase in EC cell or mast cell counts, defined as more than the mean of controls + 2 standard deviations. Enterochromaffin cell, mast cell, or lamina propria T lymphocyte numbers were poorly correlated with anxiety and depression scores in the IBS group.

Conclusions:  Enterochromaffin cells, mast cells, and lamina propria T lymphocytes significantly increase in PI IBS, whereas only mast cells significantly increase in non-PI IBS-D. Such histopathological changes do not seem to be directly associated with psychological factors.

The alteration of enterochromaffin cell, mast cell, and lamina propria T lymphocyte numbers in irritable bowel syndrome and its relationship with psychological factors

Heat shock proteins (HSPs) are crucial for the maintenance of cell integrity during normal cellular growth as well as during pathophysiological conditions. While functioning mainly as molecular chaperones, HSPs also appear to be involved in diverse biological activities, such as apoptosis, carcinogenesis, and cytoprotection from cytotoxic damage. Infection with Helicobacter pylori causes inflammation in the gastric mucosa, leading to gastritis, gastric ulcers, duodenal ulcer disease, and even gastric cancer, but the role of HSPs in H. pylori-associated gastropathy is not known. Using two-dimensional electrophoretic analysis, we have observed significant shifts in HSP profiles after H. pylori infection in RGM-1 cells. We therefore evaluated the effect of treatments that induce HSPs on H. pylori-induced inducible nitric oxide synthase (iNOS) expression. We found that H. pylori infection significantly attenuated the expression of HSP70, whereas exposure of cells to noncytotoxic heat shock or geranylgeranylacetone restored HSP70 expression, as well as suppressing the expression of iNOS, a major cause of H. pylori-induced gastric tissue damage. Our results suggest that induction of HSP70 confers cytoprotection against H. pylori infection by inhibiting the expression of iNOS. In conclusion, these results provide important insights into the flux in HSPs profiles in response to H. pylori infection and highlight the cytoprotective role of HSP70 in H. pylori infection.

Restoration of heat shock protein70 suppresses gastric mucosal inducible nitric oxide synthase expression induced by Helicobacter pylori.

Though ulcerative colitis (UC)-associated colon cancer develops from dysplastic lesions caused by chronic inflammation, the specific mechanistic link between chronic inflammation and carcinogenesis in colon has not been integrated into molecular understanding. We therefore established an experimental animal model for colitic cancer, and used proteomic analysis, based on 2-DE and MALDI-TOF MS, to identify proteins involved in colitic cancer. In our model, 6-week-old C57BL/6J mice were exposed to 15 cycles of dextran sodium sulfate (DSS), with each cycle consisting of 0.7% DSS for 1 week followed by distilled water for 10 days. Colorectal tumors developed in 22 of 24 mice (91.6%), with a tumor multiplicity of 1.727 per tumor-bearing mouse. Comparative 2-DE analysis showed that 38 protein spots were differentially expressed in colon tumors and normal colon. We identified 27 of these proteins, including GRP94, HSC70, enolase, prohibitin, and transgelin. The reduction of transgelin expression in mouse colon tumors was confirmed by Western blotting and immunohistochemistry. We also found that transgelin expression was significantly reduced in human colon tumors compared with adjacent nontumorous tissues. In conclusion, these results suggest that loss of transgelin could be a candidate for biomarker of repeated colitis-associated colon cancer.

Loss of transgelin in repeated bouts of ulcerative colitis-induced colon carcinogenesis.

The H+/K+-ATPase of gastric parietal cell exchanges luminal K+ for cytoplasmic H+, of which outcome is gastric acidification with outflux of hydronium ion (H3O+). Secretion of gastric acid from the H+/K+-ATPase is stimulated by neuronal sensing and elaborately regulated various neuronal transmitters and hormones, consequently resulting in anchoring of the H+/K+-ATPase in canaliculi membrane of gastric parietal cell. Since hypersecretion of gastric acid or a defect of its barrier function is considered as a principal casual factor in the acid-related diseases such as duodenal and gastric ulcer, reflux esophagitis, and some types of gastritis, the development of anti-secretory agents including PPIs (proton pump inhibitors) and H2-RAs (histamine type 2 receptor antagonists) has revolutionized during the second millennium. Similar considerations applying to design of compounds substituting K+ led to the development of acid pump antagonists (APAs), of which advantages are independent of secretory status, no lag time required, reversible in actions allowing “on-demand dosage”. Our recent studies revealed that these inhibitors of H+/K+-ATPase could be extensively applied for the selective induction of cancer cell apoptosis, a significant anti-inflammatory and gastroprotective action far beyond acid suppression. In the current review, we described the mechanistic regulation of gastric acid secretion with pump inhibitor, the difference and characteristics between PPI and APA based on the molecular mechanism, and their new applications beyond acid suppression.

The novel acid pump antagonists for anti-secretory actions with their peculiar applications beyond acid suppression

Ginseng, the root of Panax ginseng C.A. Meyer, has been reported to exert preventive effects on gastropathy via anti-oxidative and anti-inflammatory actions. In this study, we investigated the protective effects of ginseng against ethanol-induced gastric damages in rat. To examine the preventive effect of ginseng, rats received two different ginseng extracts, A and B, 1 h prior to the administration of ethanol. Pretreatment of rats with ginseng extract A and B attenuated the ethanol-induced gastric lesions by 111 ± 48 and 142 ± 47 mm2 compared to control group (164 ± 54 mm2). Significant induction of cytoprotective heat-shock proteins HSP27 and HSP70 was found in the ginseng-administrated rats, suggesting that the restoration of the proteins might contribute to prevention of ethanol-induced gastric injuries. It is, therefore, suggested that ginseng has a protective effect against ethanol-induced gastric damages by induction of heat-shock proteins 70 and 27.

Ginseng, the Root of Panax ginseng C.A. Meyer, Protects Ethanol-Induced Gastric Damages in Rat through the Induction of Cytoprotective Heat-Shock Protein 27

Dong Kyu Kim

Papers

The alteration of enterochromaffin cell, mast cell, and lamina propria T lymphocyte numbers in irritable bowel syndrome and its relationship with psychological factors

Restoration of heat shock protein70 suppresses gastric mucosal inducible nitric oxide synthase expression induced by Helicobacter pylori.

Loss of transgelin in repeated bouts of ulcerative colitis-induced colon carcinogenesis.

The novel acid pump antagonists for anti-secretory actions with their peculiar applications beyond acid suppression

Ginseng, the Root of Panax ginseng C.A. Meyer, Protects Ethanol-Induced Gastric Damages in Rat through the Induction of Cytoprotective Heat-Shock Protein 27