Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0043352 (xerostomia)
 4,250 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Xerostomia as a result of salivary gland damage is a permanent and debilitating side effect of radiotherapy for head and neck cancers. Effective treatments for protecting, or restoring, salivary gland function are not available. Here we report that irradiation treatment leads to activation of the calcium-permeable channel, transient potential melastatin-like 2 (TRPM2), via stimulation of poly-ADP-ribose polymerase. Importantly, irradiation induced an irreversible loss of salivary gland fluid secretion in TRPM2+/+ mice while a transient loss was seen in TRPM2-/- mice with >60% recovery by 30 days after irradiation. Treatment of TRPM2+/+ mice with the free radical scavenger Tempol or the PARP1 inhibitor 3-aminobenzamide attenuated irradiation-induced activation of TRPM2 and induced significant recovery of salivary fluid secretion. Furthermore, TPL (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl) induced complete recovery of function in irradiated TRPM2-/- mice. These novel data demonstrate that TRPM2 is activated by irradiation, via PARP1 activation, and contributes to irreversible loss of salivary gland function.
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PMID:Loss of TRPM2 function protects against irradiation-induced salivary gland dysfunction. 2344 43

Radiation therapy is commonly used to treat patients with head and neck squamous cell carcinoma (HNSCC). One of the major side effects of radiotherapy is injury to the salivary glands (SG), which is thought to be mediated by microvascular dysfunction leading to permanent xerostomia. The goal of this study was to elucidate the mechanism of radiation-induced microvasculature damage and its impact on SG function. We measured bovine aortic endothelial cell (BAEC) apoptosis and ceramide production in response to 5 Gy irradiation, either alone or with reactive oxygen species (ROS) scavengers. We then investigated the effect of a single 15 Gy radiation dose on murine SG function. BAECs exposed to 5 Gy underwent apoptosis with increased ceramide production, both prevented by ROS scavengers. Among the 15 Gy irradiated mice, there was considerable weight loss, alopecia and SG hypofunction manifested by reduced saliva production and lower lysozyme levels. All of these effects, except for the lysozyme levels, were prevented by pretreatment with ROS scavengers. Microvessel density was significantly lower in the SG of irradiated mice compared to the control group, and this effect was significantly attenuated by pretreatment with Tempol. This study demonstrates that radiation-induced SG hypofunction is to a large extent mediated by microvascular dysfunction involving ceramide and ROS generation. These findings strongly suggest that ROS scavengers may serve as potential radioprotectors of SG function in patients undergoing radiotherapy for HNSCC.
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PMID:Radiation-Induced Microvascular Injury as a Mechanism of Salivary Gland Hypofunction and Potential Target for Radioprotectors. 2745 4