Abstract

Studies outlined in the revised competing renewal are aimed at understanding the physiologic and therapeutic effect of activating ADO A3 receptors (Rs) in experimental models of colitis.
Three specific aim 's are addressed in distal colon, the therapeutic target for the A3R agonist IB-MECA in TNBS colitis.
AIM 1 : Determine the physiological role of ADOA3Rs in neural reflexes of the rat distal colon. Hypothesis 1.1 is tested that IB-MECA acts at A3Rs on enteric neurons to inhibit propulsion by recording from AH sensory neurons identified morphologically by neurobiotin injection or S descending motor neurons to circular muscle (CM) identified physiologically by retrograde labeling with Oil. A3 modulation in the inhibitory motor limb of reflex is determined by experiments on CM relaxation, VIP release, strain-gauge recording of large amplitude contractions or peristaltic propulsion of a fecal pellet. Endogenous ADO release will be quantitated by mass spectrometry.
AIM 2. Determine the role of A3Rs as a therapeutic target in experimental models of colitis. Hypothesis 2.1 is tested that A3Rs mediate the therapeutic effect of IB- MECA in chronic inflammation induced by TNBS in rats. A1 or A3 antagonists will prove A3R involvement. Hypothesis 2.2 is tested that A3Rs confer protection in genomic models of colitis. It is tested using DSS in C57BL/6 A3 KO or FVB/N profilin transctenic mice with 8-fold up-regulation of A3Rs. Transgenic manipulation of A3R may provide unequivocal proof for receptor signaling and A3R-IB-MECA protection in murine colitis.
AIM 3. Determine the cellular and intracellular mechanisms involved in the beneficial effects of IB-MECA treatment in TNBS colitis. Hypothesis 3.1 tests if activation of A3Rs provides neuroprotection in TNBS colitis. It is tested by looking at reversal of neural gene dysregulation, sensory AH and EC cell hyperesponsiveness or H202 oxidant-activation of neurons, analysis ofeADO and eADO effects at A3Rs. The therapeutic study with oral IB-MECA more closely parallels acute ex-vivo studies and tests its effect once the damage has occurred in TNBS colitis. Hypothesis 3.2 tests ifadenosine A3R activation inhibits oxygen free radicals in rat TNBS colitis using EPRI analysis of tissue and neutrophil free radicals, and gene microarray of oxidant and antioxidant genes. These mechanistic studies willprovide new insights into A3R regulation as a therapeutic target in experimental models oflBD and may pave the way towards translational studies.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK044179-15
Application #
7740200
Study Section
Clinical and Integrative Gastrointestinal Pathobiology Study Section (CIGP)
Program Officer
Serrano, Jose
Project Start
1992-04-01
Project End
2012-11-30
Budget Start
2009-12-01
Budget End
2012-11-30
Support Year
15
Fiscal Year
2010
Total Cost
$267,665
Indirect Cost

  Institution

Name
Ohio State University
Department
Anesthesiology
Type
Schools of Medicine
DUNS #
832127323
City
Columbus
State
OH
Country
United States
Zip Code
43210

  Publications

Liñán-Rico, A; Wunderlich, J E; Enneking, J T et al. (2015) Neuropharmacology of purinergic receptors in human submucous plexus: Involvement of P2X?, P2X?, P2X? channels, P2Y and A? metabotropic receptors in neurotransmission. Neuropharmacology 95:83-99
Ochoa-Cortes, Fernando; Liñán-Rico, Andromeda; Jacobson, Kenneth A et al. (2014) Potential for developing purinergic drugs for gastrointestinal diseases. Inflamm Bowel Dis 20:1259-87
Liñán-Rico, Andrómeda; Wunderlich, Jacqueline E; Grants, Iveta S et al. (2013) Purinergic autocrine regulation of mechanosensitivity and serotonin release in a human EC model: ATP-gated P2X3 channels in EC are downregulated in ulcerative colitis. Inflamm Bowel Dis 19:2366-79
Ren, Tianhua; Grants, Iveta; Alhaj, Mazin et al. (2011) Impact of disrupting adenosine A? receptors (A??/? AR) on colonic motility or progression of colitis in the mouse. Inflamm Bowel Dis 17:1698-713
Rybaczyk, Leszek; Rozmiarek, Andrew; Circle, Kristin et al. (2009) New bioinformatics approach to analyze gene expressions and signaling pathways reveals unique purine gene dysregulation profiles that distinguish between CD and UC. Inflamm Bowel Dis 15:971-84
Bozarov, Andrey; Wang, Yu-Zhong; Yu, Jun Ge et al. (2009) Activation of adenosine low-affinity A3 receptors inhibits the enteric short interplexus neural circuit triggered by histamine. Am J Physiol Gastrointest Liver Physiol 297:G1147-62
Chen, Zhixiong; Suntres, Zach; Palmer, Jeffrey et al. (2007) Cyclic AMP signaling contributes to neural plasticity and hyperexcitability in AH sensory neurons following intestinal Trichinella spiralis-induced inflammation. Int J Parasitol 37:743-61
Guzman, Jorge; Yu, Jun Ge; Suntres, Zacharias et al. (2006) ADOA3R as a therapeutic target in experimental colitis: proof by validated high-density oligonucleotide microarray analysis. Inflamm Bowel Dis 12:766-89
Cooke, Helen J; Xue, Jianjing; Yu, Jun Ge et al. (2004) Mechanical stimulation releases nucleotides that activate P2Y1 receptors to trigger neural reflex chloride secretion in guinea pig distal colon. J Comp Neurol 469:1-15
Christofi, Fievos L; Wunderlich, Jacqueline; Yu, Jun Ge et al. (2004) Mechanically evoked reflex electrogenic chloride secretion in rat distal colon is triggered by endogenous nucleotides acting at P2Y1, P2Y2, and P2Y4 receptors. J Comp Neurol 469:16-36

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