NEW KNOWLEDGE ON THE MOLECULAR FORMS OF NEUROTROPHIN FAMILY MEMBERS IN A MAJOR PELVIC ORGAN

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 389-405-Signaling Originating from Membrane Receptors
Basic/Translational
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-396
Jayaraman Lakshmanan1, Edgar M Ruiz*1, Matt Ho1, French Samuel Williams1, Monica G Ferrini2 and Robert Morin1
1Los Angeles Bio-Medical Research Institute at Harbor UCLA Medical Center, Torrance, CA, 2Martin Luther King Hospital, Los Angeles, CA
Background and aims: A plethora of new knowledge has recently emerged supporting the view that proneurotrophins are stable molecules expressed more abundantly than mature neurotrophins in peripheral target tissues innervated by target neurons. They are biologically active and subject to anterograde and retrograde axonal transport. The rat urinary bladder, a major pelvic organ has been reported to express all four neurotrophin mRNAs. Bladder extracts were reported to contain mature neurotrophins quantifiable by ELISA but no information exists on the status of proneurotrophins in this organ. Also, published reports on neurotrophin distribution in rat bladder are quite controversial.  Here, we have examined the four neurotrophin immunostaining patterns as well as the status of their respective proneurotrophins in adult rat bladder using well characterized antibodies that are known to interact with mature neurotrophins as well as their respective proneurotrophins.

Methods: Sprague-Dawley adult female rat bladders were examined by immunohistochemistry (n=12) and molecular forms of neurotrophins examined by Western blotting (n=12) using bladder extracts prepared at physiological pH in the presence of detergents and protease inhibitors. 

Results:  The βNGF antibody immunostained structures in suburothelial mucosa while BDNF and NT3 antibodies immunostained the urothelial cells. The NT-4 antibody immunostained the neural plexuses in suburothelial regions. The βNGF antibody immunostained nerve fibers innervating the detrusor smooth muscle layers while the BDNF and NT3 antibodies immunostained the detrusor smooth muscle cells. The NT4 antibody immunostained the neural plexus localized between muscle layers.  βNGF antibody identified a 75, 35, 25 and 13kDa proteins. The BDNF antibody identified a 150 and a 15kDa protein. The NT-3 antibody identified a 250 and 18kDa protein and the NT-4/5 antibody identified a 25kDa protein.

Summary: All four neurotrophin antibodies distinctly immunostained the urothelial and muscle layers in the rat bladder. Our finding identified for the first time the high molecular weight neurotrophin precursor molecules in this organ. The molecular sizes of the neurotrophin precursors are in close agreement with studies reported in the innervated peripheral organs, central nervous system and cultured immune cells.

Conclusion:  We postulate that neurotrophin precursors are likely to play a key role in bladder functions. Any aberration in proneurotrophin expression, processing and function could contribute to the pathophysiology of painful bladder syndrome and other bladder dysfunctions particularly in the elderly.

Nothing to Disclose: JL, EMR, MH, FSW, MGF, RM

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: By a grant from the Department of Pathology, Harbor UCLA Medical Center