Diarrheal diseases remain a leading cause of deaths in children (~1.2 million/year) worldwide. In addition to its significant mortality and morbidity i developing countries, even in western countries, diarrhea associated with IBD and infection by food-borne pathogens or hospital acquired infections remains a major healthcare challenge. Therefore, better and novel treatment modalities are needed. In this regard, studies during our previous funding cycle provided pioneering in vitro and in vivo evidence for a potential probiotic Lactobacillus acidophilus (LA) based approach for the amelioration of diarrhea. We demonstrated that the mechanism of LA-mediated antidiarrheal effects involved stimulation of intestinal NaCl absorption, involving upregulation of the activities of NHE3 and DRA (the key intestinal apical membrane Na+/H+ and Cl-/HCO3- exchangers, respectively). Most importantly, the bacteria-free culture supernatant (CS) of LA was equally effective in stimulating NaCl absorption, defining a novel therapeutic modality to utilize bacteria-derived bioactive molecules, rather than live bacteria, for treating diarrheal disorders. Our studies further indicated that LA r LA- CS-induced enhancement of Cl-/HCO3- exchange activity involved increased levels of DRA on the apical membrane as well as its increased expression via transcriptional mechanisms. However, detailed cellular and molecular events governing LA- or LA-CS-induced alterations in DRA trafficking and regulation of DRA expression at the transcriptional level under normal physiology and under disease states are not known. Therefore, based on our published reports and strong preliminary data presented here we hypothesized that bacteria-free culture supernatant of L. acidophilus stimulates intestinal epithelial Cl-/HCO3- exchange activity via multiple mechanisms involving alterations of both intracellular trafficking of DRA as well as DRA expression. We also hypothesize that LA or LA-CS can combat the repression of DRA in models of IBD. We will test these hypotheses by systematic set of approaches utilizing both in vitro and in vivo models and state-of-the-art imaging and advanced molecular biology techniques. Studies proposed in Specific Aim 1 will investigate the mechanisms of LA-CS induced modulation of DRA trafficking in Caco2 cell monolayers and elucidate the role of lipid rafts, cytoskeletal and PDZ proteins;
Specific Aim 2 will focus on elucidating mechanisms of LA-CS-induced stimulation of DRA transcription in Caco2 cells;and studies in Specific Aim 3 will examine the effects of short-term as well as long-term LA treatment on DRA function and membrane targeting mechanisms in in-vivo mouse models including IBD models. These studies will not only enhance our understanding of the mechanisms underlying proabsorptive/antidiarrheal role of probiotic LA but will also highlight the potential of the secreed bioactive molecules in LA-CS in combating the IBD associated diarrhea.

Public Health Relevance

Diarrheal diseases still result in ~1.2 million deaths/year worldwide in children under the age of five. In this regard, probiotics are beneficial bacteria which have been shown to be useful in clinical trials in treating diarrheal diseases. The studies proposed in this application will determine molecular and cellular mechanisms responsible for antidiarrheal effects of a probiotic bacteria Lactobacillus acidophilus. Understanding of the mechanisms of its beneficial effects and the bacteria derived molecules responsible for them may assist in designing novel and superior treatment strategies in for diarrheal diseases.

Agency
National Institute of Health (NIH)
Type
Research Project (R01)
Project #
5R01DK081858-06
Application #
8688224
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Grey, Michael J
Project Start
Project End
Budget Start
Budget End
Support Year
6
Fiscal Year
2014
Total Cost
Indirect Cost
Name
University of Illinois at Chicago
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
City
Chicago
State
IL
Country
United States
Zip Code
60612
Anbazhagan, Arivarasu N; Priyamvada, Shubha; Alakkam, Anas et al. (2016) Transcriptional modulation of SLC26A3 (DRA) by sphingosine-1-phosphate. Am J Physiol Gastrointest Liver Physiol 310:G1028-35
Priyamvada, Shubha; Anbazhagan, Arivarasu N; Kumar, Anoop et al. (2016) Lactobacillus acidophilus stimulates intestinal P-glycoprotein expression via a c-Fos/c-Jun-dependent mechanism in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 310:G599-608
Asghar, M Nadeem; Priyamvada, Shubha; Nyström, Joel H et al. (2016) Keratin 8 knockdown leads to loss of the chloride transporter DRA in the colon. Am J Physiol Gastrointest Liver Physiol 310:G1147-54
Anbazhagan, Arivarasu N; Priyamvada, Shubha; Gujral, Tarunmeet et al. (2016) A novel anti-inflammatory role of GPR120 in intestinal epithelial cells. Am J Physiol Cell Physiol 310:C612-21
Gujral, Tarunmeet; Kumar, Anoop; Priyamvada, Shubha et al. (2015) Mechanisms of DRA recycling in intestinal epithelial cells: effect of enteropathogenic E. coli. Am J Physiol Cell Physiol 309:C835-46
Priyamvada, Shubha; Anbazhagan, Arivarasu N; Gujral, Tarunmeet et al. (2015) All-trans-retinoic Acid Increases SLC26A3 DRA (Down-regulated in Adenoma) Expression in Intestinal Epithelial Cells via HNF-1β. J Biol Chem 290:15066-77
Kumar, Anoop; Alrefai, Waddah A; Borthakur, Alip et al. (2015) Lactobacillus acidophilus counteracts enteropathogenic E. coli-induced inhibition of butyrate uptake in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 309:G602-7
Nazir, Saad; Kumar, Anoop; Chatterjee, Ishita et al. (2015) Mechanisms of Intestinal Serotonin Transporter (SERT) Upregulation by TGF-β1 Induced Non-Smad Pathways. PLoS One 10:e0120447
Muthusamy, Saminathan; Malhotra, Pooja; Hosameddin, Mobashir et al. (2015) N-glycosylation is essential for ileal ASBT function and protection against proteases. Am J Physiol Cell Physiol 308:C964-71
Priyamvada, Shubha; Gomes, Rochelle; Gill, Ravinder K et al. (2015) Mechanisms Underlying Dysregulation of Electrolyte Absorption in Inflammatory Bowel Disease-Associated Diarrhea. Inflamm Bowel Dis 21:2926-35

Showing the most recent 10 out of 45 publications