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colitis actinic

Kuldeep Verma, Tomoyoshi Nozaki, Sunando Datta
Entamoeba histolytica, the causative agent of amoebic colitis and liver abscess in human, ingests the intestinal bacteria and variety of host cells. Phagocytosis of bacteria by the amebic trophozoite has been reported to be important for the virulence of the parasite. Here, we set out to characterize different stages of phagocytosis of type 1 E. coli and investigated the role of a set of amoebic Rab GTPases in the process. The localizations of the Rab GTPases during different stages of the phagocytosis were investigated using laser scanning confocal microscopy and their functional relevance were determined using fluorescence activated cell sorter based assay as well as colony forming unit assay...
September 24, 2016: Molecular Microbiology
Kenji Suzuki, Somasundaram Arumugam, Junji Yokoyama, Yusuke Kawauchi, Yutaka Honda, Hiroki Sato, Yutaka Aoyagi, Shuji Terai, Kazuichi Okazaki, Yasuo Suzuki, Shuji Mizumoto, Kazuyuki Sugahara, Raja Atreya, Markus F Neurath, Kenichi Watanabe, Taishi Hashiguchi, Hiroyuki Yoneyama, Hitoshi Asakura
Induction of mucosal healing (MH) is an important treatment goal in inflammatory bowel disease (IBD). Although the molecular mechanisms underlying MH in IBD is not fully explored, local fibrosis would contribute to interfere mucosal repair. Carbohydrate sulfotransferase 15 (CHST15), which catalyzes sulfation of chondroitin sulfate to produce rare E-disaccharide units, is a novel mediator to create local fibrosis. Here we have used siRNA-based approach of silencing CHST15 in dextran sulfate sodium (DSS) induced colitis in mice, human colon fibroblasts and cancer cell lines...
2016: PloS One
Braden M Roth, Kristen M Varney, Richard R Rustandi, David J Weber
Once considered a relatively harmless bacterium, Clostridium difficile has become a major concern for healthcare facilities, now the most commonly reported hospital-acquired pathogen. C. difficile infection (CDI) is usually contracted when the normal gut microbiome is compromised by antibiotic therapy, allowing the opportunistic pathogen to grow and produce its toxins. The severity of infection ranges from watery diarrhea and abdominal cramping to pseudomembranous colitis, sepsis, or death. The past decade has seen a marked increase in the frequency and severity of CDI among industrialized nations owing directly to the emergence of a highly virulent C...
October 2016: Biomolecular NMR Assignments
Yamato Tanabe, Soichiro Sasaki, Naofumi Mukaida, Tomohisa Baba
We previously demonstrated that cancer-associated fibroblasts (CAFs) accumulate at tumor sites through the interaction between a chemokine, CCL3, and its receptor, CCR5, in the late phase of colitis-associated colon carcinogenesis. Here we examined the effect of a CCR5 antagonist, maraviroc, on tumor growth arising from the orthotopic injection of mouse or human colon cancer cell lines into the cecal wall by focusing on CAFs. Orthotopic injection of either cell line caused tumor formation together with leukocyte infiltration and fibroblast accumulation...
June 22, 2016: Oncotarget
Sarah Lynn Martz, Mabel Guzman-Rodriguez, Shu-Mei He, Curtis Noordhof, David John Hurlbut, Gregory Brian Gloor, Christian Carlucci, Scott Weese, Emma Allen-Vercoe, Jun Sun, Erika Chiong Claud, Elaine Olga Petrof
BACKGROUND: A defined Microbial Ecosystem Therapeutic (MET-1, or "RePOOPulate") derived from the feces of a healthy volunteer can cure recurrent C. difficile infection (rCDI) in humans. The mechanisms of action whereby healthy microbiota protect against rCDI remain unclear. Since C. difficile toxins are largely responsible for the disease pathology of CDI, we hypothesized that MET-1 exerts its protective effects by inhibiting the effects of these toxins on the host. METHODS: A combination of in vivo (antibiotic-associated mouse model of C...
June 21, 2016: Journal of Gastroenterology
Nour Eissa, Hayam Hussein, Hongxing Wang, Mohammad F Rabbi, Charles N Bernstein, Jean-Eric Ghia
BACKGROUND: Many animal models have been developed to characterize the complexity of colonic inflammation. In dextran sodium sulfate (DSS) experimental colitis in mice the choice of reference genes is critical for accurate quantification of target genes using quantitative real time PCR (RT-qPCR). No studies have addressed the performance of reference genes in mice DSS-experimental colitis. This study aimed to determine the stability of reference genes expression (RGE) in DSS-experimental murine colitis...
2016: PloS One
So-Young Lee, Hwain Kim, Kyoungmi Kim, Hyunji Lee, Seungbok Lee, Daekee Lee
Coordinated regulation of the actin cytoskeleton by the Rho GTPase family is required for the maintenance of polarity in epithelial cells as well as for their proliferation and migration. A RhoGTPase-activating protein 17 (Arhgap17) is known to be involved in multiple cellular processes in vitro, including the maintenance of tight junctions and vesicle trafficking. However, the function of Arhgap17 has not been studied in the physiological context. Here, we generated Arhgap17-deficient mice and examined the effect in the epithelial and mucosal barriers of the intestine...
2016: Scientific Reports
Nayden G Naydenov, Alex Feygin, Dongdong Wang, John F Kuemmerle, Gianni Harris, Mary Anne Conti, Robert S Adelstein, Andrei I Ivanov
The actin cytoskeleton is a critical regulator of intestinal mucosal barrier permeability, and the integrity of epithelial adherens junctions (AJ) and tight junctions (TJ). Non muscle myosin II (NM II) is a key cytoskeletal motor that controls actin filament architecture and dynamics. While NM II has been implicated in the regulation of epithelial junctions in vitro, little is known about its roles in the intestinal mucosa in vivo. In this study, we generated a mouse model with an intestinal epithelial-specific knockout of NM IIA heavy chain (NM IIA cKO) and examined the structure and function of normal gut barrier, and the development of experimental colitis in these animals...
2016: Scientific Reports
Andrew Baird, Raul Coimbra, Xitong Dang, Brian P Eliceiri, Todd W Costantini
BACKGROUND: The α7-subunit of the α7-nicotinic acetylcholine receptor (α7-nAChR) is an obligatory intermediate for the anti-inflammatory effects of the vagus nerve. But in humans, there exists a second gene called CHRFAM7A that encodes a dominant negative α7-nAChR inhibitor. Here, we investigated whether their expression was altered in inflammatory bowel disease (IBD) and colon cancer. METHODS: Quantitative RT-PCR measured gene expression of human α7-nAChR gene (CHRNA7), CHRFAM7A, TBC3D1, and actin in biopsies of normal large and small intestine, and compared to their expression in biopsies of ulcerative colitis, Crohn's disease, and colon cancer...
June 2016: BBA Clinical
Chiara Ippolito, Rocchina Colucci, Cristina Segnani, Mariella Errede, Francesco Girolamo, Daniela Virgintino, Amelio Dolfi, Erika Tirotta, Piero Buccianti, Giulio Di Candio, Daniela Campani, Maura Castagna, Gabrio Bassotti, Vincenzo Villanacci, Corrado Blandizzi, Nunzia Bernardini
BACKGROUND AND AIMS: Intestinal fibrosis is a complication of inflammatory bowel disease [IBD]. Although fibrostenosis is a rare event in ulcerative colitis [UC], there is evidence that a fibrotic rearrangement of the colon occurs in the later stages. This is a retrospective study aimed at examining the histopathological features of the colonic wall in both short-lasting [SL] and long-lasting [LL] UC. METHODS: Surgical samples of left colon from non-stenotic SL [≤ 3 years, n = 9] and LL [≥ 10 years, n = 10] UC patients with active disease were compared with control colonic tissues from cancer patients without UC [n = 12] to assess: collagen and elastic fibres by histochemistry; vascular networks [CD31/CD105/nestin] by immunofluorescence; parameters of fibrosis [types I and III collagen, fibronectin, RhoA, alpha-smooth muscle actin [α-SMA], desmin, vimentin], and proliferation [proliferating nuclear antigen [PCNA]] by western blot and/or immunolabelling...
October 2016: Journal of Crohn's & Colitis
Dongdong Wang, Nayden G Naydenov, Alex Feygin, Somesh Baranwal, John F Kuemmerle, Andrei I Ivanov
The actin cytoskeleton is a crucial regulator of the intestinal mucosal barrier, controlling the assembly and function of epithelial adherens and tight junctions (AJs and TJs). Junction-associated actin filaments are dynamic structures that undergo constant turnover. Members of the actin-depolymerizing factor (ADF) and cofilin protein family play key roles in actin dynamics by mediating filament severing and polymerization. We examined the roles of ADF and cofilin-1 in regulating the structure and functions of AJs and TJs in the intestinal epithelium...
April 2016: American Journal of Pathology
Claudia Frädrich, Lara-Antonia Beer, Ralf Gerhard
Clostridium difficile infections can induce mild to severe diarrhoea and the often associated characteristic pseudomembranous colitis. Two protein toxins, the large glucosyltransferases TcdA and TcdB, are the main pathogenicity factors that can induce all clinical symptoms in animal models. The classical molecular mode of action of these homologous toxins is the inhibition of Rho GTPases by mono-glucosylation. Rho-inhibition leads to breakdown of the actin cytoskeleton, induces stress-activated and pro-inflammatory signaling and eventually results in apoptosis of the affected cells...
January 2016: Toxins
Peter S Hegan, Dmitri V Kravtsov, Christina Caputo, Marie E Egan, Nadia A Ameen, Mark S Mooseker
Myosin Ia (Myo1a), the most prominent plus-end directed motor and myosin VI (Myo6) the sole minus-end directed motor, together exert opposing tension between the microvillar (MV) actin core and the apical brush border (BB) membrane of the intestinal epithelial cell (IEC). Mice lacking Myo1a or Myo6 each exhibit a variety of defects in the tethering of the BB membrane to the actin cytoskeleton. Double mutant (DM) mice lacking both myosins revealed that all the defects observed in either the Myo1a KO or Snell's waltzer (sv/sv) Myo6 mutant mouse are absent...
September 2015: Cytoskeleton
Jessica R de Bruyn, Sybren L Meijer, Manon E Wildenberg, Willem A Bemelman, Gijs R van den Brink, Geert R D'Haens
BACKGROUND: Intestinal fibrosis is a process driven by chronic inflammation leading to increased presence of myofibroblasts and collagen deposition. Although strictures are rarely seen in ulcerative colitis [UC], longstanding disease is believed to cause fibrosis resulting in altered bowel function. METHODS: The presence of fibrosis was studied in colectomy specimens from patients with recent-onset UC refractory to medical treatment [n = 13] and longstanding UC [n = 16], and colon cancer patients without UC [n = 7] as controls...
November 2015: Journal of Crohn's & Colitis
Peili Chen, Danika Bakke, Lauren Kolodziej, James Lodolce, Christopher R Weber, David L Boone, F Gary Toback
BACKGROUND: A peptide derived from Antrum Mucosal Protein (AMP)-18 (gastrokine-1) reduces the extent of mucosal erosions and clinical severity in mice with dextran sulfate sodium-induced colonic injury. This study set out to determine if AMP peptide was also therapeutic for immune- and cytokine-mediated mouse models of intestinal injury and inflammatory bowel diseases by enhancing and stabilizing tight junctions. METHODS: Therapeutic effects of AMP peptide were examined in interleukin-10-deficient and a T-cell adoptive transfer models of colitis in immunodeficient recombinase activating gene-1 knock-out (RAG-1-/-) mice...
October 2015: Inflammatory Bowel Diseases
Kyle Leonard O'Hagan, Jinyong Choi, Olga Pryshchep, Jonathan Chernoff, Hyewon Phee
Although significant effort has been devoted to understanding the thymic development of Foxp3(+) regulatory T cells (Tregs), the precise signaling pathways that govern their lineage commitment still remain enigmatic. Our findings show a novel role for the actin cytoskeletal remodeling protein, p21-activated kinase 2 (Pak2), in Treg development and homeostasis. The absence of Pak2 in T cells resulted in a marked reduction in both thymus- and peripherally derived Tregs, accompanied by the development of spontaneous colitis in Pak2-deficient mice...
August 15, 2015: Journal of Immunology: Official Journal of the American Association of Immunologists
Casey N Petrie, Michael N Armitage, Michael D Kawaja
Nerve growth factor (NGF) levels increase in response to inflammation of the mammalian colon. The precise cellular sources of colonic NGF synthesis, however, remain elusive. Using lines of transgenic mice that express enhanced green fluorescent protein (EGFP) under the control of the NGF promoter, we found a subpopulation of adendritic EGFP(+) neurons in the myenteric plexus. These colonic EGFP(+) neurons display positive immunostaining for calretinin but not nitric oxide synthase 1 (NOS1) two biomarkers of mouse myenteric neurons...
September 2015: Experimental Neurology
Hiroki Saijo, Norifumi Tatsumi, Seiji Arihiro, Tomohiro Kato, Masataka Okabe, Hisao Tajiri, Hisashi Hashimoto
Ulcerative colitis (UC) is a representative clinical manifestation of inflammatory bowel disease that causes chronic gastrointestinal tract inflammation. Dextran sulfate sodium (DSS)-induced colitis mice have been used to investigate UC pathogenesis, and in this UC model, disturbance and impairment of the mucosal epithelium have been reported to cause colitis. However, how DSS sporadically breaks down the epithelium remains unclear. In this study, we focused on the colonic microcirculation and myenteric neurons of DSS-induced colitis...
July 2015: Laboratory Investigation; a Journal of Technical Methods and Pathology
Sarah Hemmasi, Bernd A Czulkies, Björn Schorch, Antonia Veit, Klaus Aktories, Panagiotis Papatheodorou
CDT (Clostridium difficile transferase) is a binary, actin ADP-ribosylating toxin frequently associated with hypervirulent strains of the human enteric pathogen C. difficile, the most serious cause of antibiotic-associated diarrhea and pseudomembranous colitis. CDT leads to the collapse of the actin cytoskeleton and, eventually, to cell death. Low doses of CDT result in the formation of microtubule-based protrusions on the cell surface that increase the adherence and colonization of C. difficile. The lipolysis-stimulated lipoprotein receptor (LSR) is the host cell receptor for CDT, and our aim was to gain a deeper insight into the interplay between both proteins...
May 29, 2015: Journal of Biological Chemistry
H-Q Du, X Zhang, Y-F An, Y Ding, X-D Zhao
The Wiskott-Aldrich syndrome protein (WASp) is an important regulator of the actin cytoskeleton and is required for immune cell function. WASp deficiency causes a marked reduction in major mature peripheral B cell subsets, particularly marginal zone (MZ) B cells. We hypothesized that WASp deficiency may also lead to a reduction of regulatory B cells (known as B10 cells) belonging to a novel subset of B cells. And in consideration of the key role of B10 cells play in maintaining peripheral tolerance, we conjectured that a deficit of these cells could contribute to the autoimmunity in patients with Wiskott-Aldrich syndrome (WAS)...
June 2015: Scandinavian Journal of Immunology
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