UIC - DDN - Dr. Alrefai

Waddah A. Alrefai, M.D.
Assistant Professor of Medicine

CONTACT

Section of Digestive Diseases and Nutrition
University of Illinois at Chicago
840 South Wood Street (M/C 716)
Chicago, Illinois 60612
Telephone: 312-569-7429
Fax: 312-569-7458
E-mail

EDUCATION & TRAINING

Medical School: College of Medicine, University of Aleppo, Aleppo, Syria
Post-Doc Fellowship: Rush University, Chicago, Illinois
Post-Doc Fellowship: University of Illinois at Chicago, Chicago, Illinois

RESEARCH INTERESTS

My research focuses mainly on studying the regulation of intestinal bile acid absorption with special emphasis on its role in cholesterol homeostasis. The majority of bile acids are absorbed in the intestine via the ileal A pical S odium dependent B ile acid T ransporter (ASBT). We employ both in vitro and in vivo models as well as biochemical and molecular biology techniques to elucidate the molecular mechanisms involved in the regulation of ileal ASBT and to determine their role in the pathophysiology of cholesterol imbalance associated with diseases such as diabetes mellitus and hypercholesterolemia.

I am also interested in investigating the role of Down Regulated in Adenoma gene (DRA) in human intestinal chloride absorption. DRA has been shown to be mutated in congenital chloride diarrhea disorder characterized by infantile diarrhea with an impaired ileal and colonic Cl - /HCO 3 - exchange activity. My studies are aimed to investigate the role of DRA in intestinal Cl- /HCO 3 - exchange process, to study its regulation and to examine its protein-protein and functional interactions with other intestinal anion exchangers and transporters involved in NaCl absorption in the human intestine.

PUBLICATIONS

1-P.K.Dudeja, N.Hafez, S.Tyagi, C.A.Gailey, M.Toofanfard, W.A.Alrefai, K.Ramaswamy and F.J.Al-Bazzazz. Expression of the Na + / H + and Cl - / HCO 3 - Exchanger Isoforms in the Proximal and Distal Human Airways . Am. J. of Physiol. Lung Cell. Mol. Physiol; 276: L971-L978, 1999.

2-Tyagi, V.Joshi, E.J.Cragoe Jr, W.A.Alrefai, K.Ramaswamy and P.K.Dudeja. Na + /H + Exchanger of the Human Colonic Basolateral Membrane. Digestive Diseases & Sciences; 45: 2282-2289, 2000.

3- W.A.Alrefai, S.Tyagi, T.M.Nazir, J.Barakat, S.S.Anwar, C.Hadjiagapiou, D.Bavishi, J.Sahi, P.Malik, T.J.Layden, K.Ramaswamy and P.K.Dudeja. Human Intestinal Anion Exchanger Isoforms: Expression, Distribution and Membrane localization. Biochem. Biophys. Acta; 1511 (1): 17-27, 2001.

4- W.A.Alrefai, S.Tyagi, F. Mansour, S. Saksena, I. Syed, K. Ramaswamy and P.K. Dudeja. Sulfate and Chloride Transport in Caco2 Cells: Differenial Regulation by Thyroxine and the Possible Role of DRA Gene. Am. J. Physiol. Gastrointest. Liver Physiol; 280: G603-G613, 2001.

5- W.A.Alrefai, B.Scaglione-Sewell, S.Tyagi, L.Wartman, T.A.Brasitus, K.Ramaswamy and P.K.Dudeja. Differential Regulation of the Expression of Na + /H + Exchanger Isoform NHE-3 by PKC a in Caco-2 Cell Line. Am. J. Physiol. Cell Physiol. 281(5): C1551-8, 2001.

6- W.A.Alrefai, K.Ramaswamy and P.K.Dudeja. Chloride Transport in Human Distal Colonic Apical Membrane Vesicles . Digestive Diseases & Sciences. 46(10): 2209-18, 2001.

7-S.Tyagi, R.J. Kavilaveettil, W.A.Alrefai, S. Alsafwah, K.Ramaswamy and P.K.Dudeja. Evidance for the Existence of a Distinct SO 4 -- /OH - Exchange Mechanism in the Human Proximal Colonic Apical Membrane Vesicles and its Possible Role in Chloride Transport. Exp Biol Med. 226(10): 912-8, 2001.

8-R.K.Gill, S.Saksena, I.A.Syed, S.Tyagi, W.A.Alrefai , K.Ramaswamy and P.K.Dudeja. Regulation of NHE-3 in Caco2 Cells by Nitric Oxide. Am J Physiol Gastrointest Liver Physiol. 2002 Sep;283(3):G747-56.

9-S.Saksena, R.K.Gill, S.Tyagi, I.A.Syed, W.A.Alrefai, K.Ramaswamy and P.K.Dudeja. Modulation of Cl - /OH - Exchange Process in Caco2 Cells by Nitric Oxide. Am J Physiol Gastrointest Liver Physiol. 2002 Sep;283(3):G626-33.

10-S.Saksena, R.K.Gill, S.Tyagi, I.A.Syed, W.A.Alrefai, K.Ramaswamy and P.K.Dudeja. A Role for PKC- e in the Inhibition of Apical Cl - /OH - Exchange Activity in Caco2 Cells by Phorbol Ester PMA. Am J Physiol Cell Physiol. 2002 Nov;283(5):C1492-500.

11- W.A.Alrefai, S.Tyagi, R.K.Gill, S.Saksena, F.Mansour, C. Hadjiagapiou, K.Ramaswamy and P.K.Dudeja. Regulation of Butyrate Uptake in Caco2 Cells: Involvement of Monocarboxylate Transporter MCT-1. Am J Physiol Gastrointest Liver Physiol. 2004 Feb;286(2):G197-203. Epub 2003 Oct 02.

12-Saksena S, Gill RK, Tyagi S, Alrefai WA, Sarwar Z, Ramaswamy K, Dudeja PK. Involvement of c-Src and PKCdelta in the inhibition of Cl - / OH - exchange activity in Caco-2 cells by serotonin. J Biol Chem. 2005 Mar 25; 280 (12): 11859-68. [Epub ahead of print]: Jan 6, 2005.

13- Ravinder K. Gill, Seema Saksena, Sangeeta Tyagi, Waddah A. Alrefai, Jaleh Malakooti, Jerrold Turner, Krishnamurthy Ramaswamy, Pradeep K. Dudeja. Regulation of Na + /H + Exchange by Serotonin in Caco-2 Cells. Gastroenterology. 2005 Apr; 128 (4): 962-74.

14-Ravinder K.Gill, Seema Saksena, Waddah A.Alrefai, Zaheer Sarwar, Jay L.Goldstein, Robert E.Carroll, K. Ramaswamy and Pradeep K.Dudeja. Expression and Membrane Localization of MCT Isoforms Along the Length of the Human Intestine. Am J Physiol Cell Physiol. 2005 May 18; [Epub ahead of print].

15- Alrefai WA, Sarwar Z, Tyagi S, Saksena S, Dudeja PK, Gill RK. Cholesterol Modulates Human Intestinal Sodium-Dependent Bile Acid Transporter. Am J Physiol Gastrointest Liver Physiol. 2005 May; 288 (5): G978-85. [Epub ahead of print] Dec 16; 2004.

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