Vasoactive intestinal peptide inhibits TNF-α-induced apoptotic events in acinar cells from nonobese diabetic mice submandibular glands

MARIO CALAFAT; LUCIANA LAROCCA; VALERIA ROCA; VANESA HAUK; NICOLAS PREGI; ALCIRA NESSE; CLAUDIA PEREZ LEIROS

Arthritis Research & Therapy

Año: 2009 vol. 11 p. 1 - 10

1478-6354

Introduction The role of apoptotic secretory epithelium as apro-inflammatory triggering factor of exocrine dysfunction iscurrently explored in Sjogren´s syndrome patients and in thenonobese diabetic (NOD) mouse model. Vasoactive intestinalpeptide (VIP) has anti-inflammatory effects in various models ofchronic inflammation. Our goal was to analyse the effect of TNF-α on apoptotic mediators in isolated acinar cells from NODsubmandibular gland and their modulation by VIP.Methods Acinar cells were isolated from submandibular glandsof 16-week-old NOD females with salivary flow decline. AgematchedBALB/c females or eight-week-old NOD females wereused as controls. Apoptotic mediators and TNF-α receptorexpression were assessed by immunoblotting and RT-PCR,caspase 3 activity was assessed by optical density at 405 nmwith Ac-DEVD-pNA as a substrate and chromatin condensationby Hoechst stain. They were evaluated in resting conditions andafter a 3.5 or 6 hours of culture with TNF-α. VIP effects in acinarcells were assessed at 100 nM in TNF-α-treated cultures andVIP receptor functional assays by radio immunoassay (cAMP) orenzymatic detection (amylase).Results NOD acinar cells at 16 weeks present an increasedexpression of TNF-α receptor1 together with increased Bax,tumour protein 53-induced nuclear protein1α (TP53INP1α),caspase 3 activity and chromatin condensation. Acini from NODmice were more sensitive to TNF-α-induced increases ofapoptotic mediators than control cells. VIP inhibited TNF-α-induced apoptotic events through functional VPAC1 receptorscoupled to the protein kinase A (PKA) signalling pathway.Conclusions Our results indicate that acinar cells isolated fromsubmandibular glands of NOD mice with salivary dysfunctionare more sensitive to apoptosis induced by TNF-α which couldbe prevented by VIP through a PKA-mediated pathway.