The potential repertoire of the innate immune system in the bladder: expression of pattern recognition receptors in the rat bladder and a rat urothelial cell line (MYP3 cells).
OBJECTIVE
The urothelium is a frontline sensor of the lower urinary tract, sampling the bladder lumen and stimulating an immune response to infectious and noxious agents. Pattern recognition receptors (PRRs) recognize such agents and coordinate the innate response, often by forming inflammasomes that activate caspase-1 and the release of interleukin-1. We have shown the presence of one PRR (NLRP3) in the urothelia and its central role in the inflammatory response to cyclophosphamide. The purpose of this study was to (1) assess the likely range of the PPR response by assessing the repertoire present in the rat bladder and (2) determine the utility of the MYP3 rat urothelia cell line for in vitro studies by assessing its PPR repertoire and functional responsiveness.


METHODS
Immunohistochemistry was performed for seven PPRs (NLRP1, NLRP3, NLRP6, NLRP7, NLRP12, NLRC4 and AIM2) on bladder sections and MYP3 cells. For functionality, MYP3 cells were challenged with the quintessential NLRP3 activator ATP and assessed for caspase-1 activation.


RESULTS
All PPRs examined were expressed in the bladder and localized to the urothelial layer with several also in the detrusor (none in the interstitia). MYP3 cells also expressed all PRRs with a variable intracellular location. ATP-stimulated caspase-1 activity in MYP3 cells in a dose-dependent manner was reduced by knockdown of NLRP3 expression.


CONCLUSIONS
The results suggest that the bladder possesses the capacity to initiate an innate immune response to a wide array of uropathological agents and the MYP3 cells will provide an excellent investigational tool for this field.
Division of Urology, Department of Surgery, Duke University Medical Center, DUMC Box 3831, Durham, NC, 27710, USA. monty.hughes@duke.edu.|Department of Urology, Medical University of South Carolina, Charleston, SC, USA. monty.hughes@duke.edu.
Francis M
FM
Hughes
Department of Pathology and Lab Medicine, Medical University of South Carolina, Charleston, SC, USA.
David P
DP
Turner
Division of Urology, Department of Surgery, Duke University Medical Center, DUMC Box 3831, Durham, NC, 27710, USA.|Department of Urology, Medical University of South Carolina, Charleston, SC, USA.|Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA.|Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA.
J
J
Todd Purves
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002352:Carrier Proteins / Q000032:analysis / Q000235:genetics; D020170:Caspase 1 / Q000378:metabolism; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000032:analysis; D005260:Female; D055785:Gene Knockdown Techniques; D007113:Immunity, Innate; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D009419:Nerve Tissue Proteins / Q000032:analysis; D034741:RNA, Small Interfering; D051381:Rats; D017207:Rats, Sprague-Dawley; D011945:Receptors, Angiotensin / Q000032:analysis; D011956:Receptors, Cell Surface / Q000032:analysis; D051192:Receptors, Pattern Recognition / Q000032:analysis* / Q000276:immunology*; D017483:Receptors, Vasopressin / Q000032:analysis; D001743:Urinary Bladder / Q000737:chemistry* / Q000276:immunology*; D019459:Urothelium / Q000737:chemistry* / Q000187:drug effects / Q000276:immunology*
C000588601:AIM2 protein, rat; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C587634:NLRC4 protein, rat; C000610577:NLRP12 protein, rat; C000610576:NLRP7 protein, rat; D009419:Nerve Tissue Proteins; C526260:Nlrp1a protein, rat; C573346:Nlrp3 protein, rat; C456360:Nlrp6 protein, rat; D034741:RNA, Small Interfering; D011945:Receptors, Angiotensin; D011956:Receptors, Cell Surface; D051192:Receptors, Pattern Recognition; D017483:Receptors, Vasopressin; D000255:Adenosine Triphosphate; D020170:Caspase 1
Bladder; Immunity; Inflammasome; Innate; Nod-like; Urothelia