Kirsten H Limesand
Assistant Dean, Graduate Education
Professor, BIO5 Institute
Professor, Cancer Biology - GIDP
Professor, Nutritional Sciences
Professor, Physiological Sciences - GIDP
Primary Department
Department Affiliations
(520) 626-4517
Work Summary
Kirsten Limesand's research program has its foundation in radiation-induced salivary gland dysfunction; mechanisms of damage, clinical prevention measures, and restoration therapies. They utilize a number of techniques including: genetically engineered mouse models, real-time RT/PCR, immunoblotting, immunohistochemistry, primary cultures, siRNA transfections, and procedures to quantitate salivary gland physiology and integrate this information in order to understand the complete system.
Research Interest
Public Relevance Statement: Can you imagine having a mouthful of canker sores and cavities? Thousands of head and neck cancer patients suffer these consequences from radiation treatment. The Limesand lab works to prevent these side effects thereby improving patients' quality of life. Clinical Relevance: Radiation therapy for head and neck cancer causes adverse secondary side effects in the normal salivary gland including xerostomia, oral mucositis, malnutrition, and increase oral infections. Although improvements have been made in targeting radiation treatment to the tumor, the salivary glands are often in close proximity to the treatment site. The significant destruction of the oral cavity following radiation therapy results in diminished quality of life and in some cases interruptions in cancer treatment schedules. Research Interests: My research program has its foundation in radiation-induced gland dysfunction; mechanisms of damage, clinical prevention measures, and restoration therapies. Evidence suggests that salivary acinar function is compromised due to apoptosis induced by these treatments and temporary suppression of apoptotic events in salivary glands would have significant benefits to oral health. We utilize a number of techniques in my laboratory including: genetically engineered mouse models, real-time RT/PCR, immunoblotting, immunohistochemistry, primary cultures, siRNA transfections, irradiation, and procedures to quantitate salivary gland physiology. Current project areas: 1. Radiation-induced apoptosis 2. Mechanisms of preserving salivary gland function 3. Identifying the radiosensitivity of salivary gland progenitor cells 4. Restoration of salivary gland function 5. Role of autophagy in radiation-induced loss of function

Publications

Goldberg, E. L., Romero-Aleshire, M. J., Renkema, K. R., Ventevogel, M. S., Chew, W. M., Uhrlaub, J. L., Smithey, M. J., Limesand, K. H., Sempowski, G. D., Brooks, H. L., & Nikolich-Žugich, J. (2015). Lifespan-extending caloric restriction or mTOR inhibition impair adaptive immunity of old mice by distinct mechanisms. Aging cell, 14(1), 130-8.
BIO5 Collaborators
Heddwen L Brooks, Kirsten H Limesand

Aging of the world population and a concomitant increase in age-related diseases and disabilities mandates the search for strategies to increase healthspan, the length of time an individual lives healthy and productively. Due to the age-related decline of the immune system, infectious diseases remain among the top 5-10 causes of mortality and morbidity in the elderly, and improving immune function during aging remains an important aspect of healthspan extension. Calorie restriction (CR) and more recently rapamycin (rapa) feeding have both been used to extend lifespan in mice. Preciously few studies have actually investigated the impact of each of these interventions upon in vivo immune defense against relevant microbial challenge in old organisms. We tested how rapa and CR each impacted the immune system in adult and old mice. We report that each intervention differentially altered T-cell development in the thymus, peripheral T-cell maintenance, T-cell function and host survival after West Nile virus infection, inducing distinct but deleterious consequences to the aging immune system. We conclude that neither rapa feeding nor CR, in the current form/administration regimen, may be optimal strategies for extending healthy immune function and, with it, lifespan.

Morgan-Bathke, M., Lin, H. H., Ann, D. K., & Limesand, K. H. (2015). The Role of Autophagy in Salivary Gland Homeostasis and Stress Responses. Journal of dental research, 94(8), 1035-40.

Autophagy is a catabolic process that has been shown to have a role in many cellular processes including the removal of excessive or damaged proteins and protein aggregates. The salivary glands play a critical role in oral health, and their secretory capacity may be critically intertwined with the autophagic process. This review describes the role of autophagy activation in normal salivary gland homeostasis and during the glandular stress responses of therapeutic radiation, ductal ligation, autoimmunity, and salivary gland adenoid cystic carcinoma.

Lin, H. H., Lin, S. M., Chung, Y., Vonderfecht, S., Camden, J. M., Flodby, P., Borok, Z., Limesand, K. H., Mizushima, N., & Ann, D. K. (2014). Dynamic involvement of ATG5 in cellular stress responses. Cell death & disease, 5, e1478.

Autophagy maintains cell and tissue homeostasis through catabolic degradation. To better delineate the in vivo function for autophagy in adaptive responses to tissue injury, we examined the impact of compromised autophagy in mouse submandibular glands (SMGs) subjected to main excretory duct ligation. Blocking outflow from exocrine glands causes glandular atrophy by increased ductal pressure. Atg5(f/-);Aqp5-Cre mice with salivary acinar-specific knockout (KO) of autophagy essential gene Atg5 were generated. While duct ligation induced autophagy and the expression of inflammatory mediators, SMGs in Atg5(f/-);Aqp5-Cre mice, before ligation, already expressed higher levels of proinflammatory cytokine and Cdkn1a/p21 messages. Extended ligation period resulted in the caspase-3 activation and acinar cell death, which was delayed by Atg5 knockout. Moreover, expression of a set of senescence-associated secretory phenotype (SASP) factors was elevated in the post-ligated glands. Dysregulation of cell-cycle inhibitor CDKN1A/p21 and activation of senescence-associated β-galactosidase were detected in the stressed SMG duct cells. These senescence markers peaked at day 3 after ligation and partially resolved by day 7 in post-ligated SMGs of wild-type (WT) mice, but not in KO mice. The role of autophagy-related 5 (ATG5)-dependent autophagy in regulating the tempo, duration and magnitude of cellular stress responses in vivo was corroborated by in vitro studies using MEFs lacking ATG5 or autophagy-related 7 (ATG7) and autophagy inhibitors. Collectively, our results highlight the role of ATG5 in the dynamic regulation of ligation-induced cellular senescence and apoptosis, and suggest the involvement of autophagy resolution in salivary repair.

Hill, G., Headon, D., Harris, Z. I., Huttner, K., & Limesand, K. H. (2014). Pharmacological activation of the EDA/EDAR signaling pathway restores salivary gland function following radiation-induced damage. PloS one, 9(11), e112840.

Radiotherapy of head and neck cancers often results in collateral damage to adjacent salivary glands associated with clinically significant hyposalivation and xerostomia. Due to the reduced capacity of salivary glands to regenerate, hyposalivation is treated by substitution with artificial saliva, rather than through functional restoration of the glands. During embryogenesis, the ectodysplasin/ectodysplasin receptor (EDA/EDAR) signaling pathway is a critical element in the development and growth of salivary glands. We have assessed the effects of pharmacological activation of this pathway in a mouse model of radiation-induced salivary gland dysfunction. We report that post-irradiation administration of an EDAR-agonist monoclonal antibody (mAbEDAR1) normalizes function of radiation damaged adult salivary glands as determined by stimulated salivary flow rates. In addition, salivary gland structure and homeostasis is restored to pre-irradiation levels. These results suggest that transient activation of pathways involved in salivary gland development could facilitate regeneration and restoration of function following damage.

Meyer, S., Chibly, A. M., Burd, R., & Limesand, K. H. (2017). Insulin-Like Growth Factor-1-Mediated DNA Repair in Irradiated Salivary Glands Is Sirtuin-1 Dependent. Journal of dental research, 96(2), 225-232.

Ionizing radiation is one of the most common cancer treatments; however, the treatment leads to a wide range of debilitating side effects. In patients with head and neck cancer (HNC), the surrounding normal salivary gland is extremely sensitive to therapeutic radiation, and damage to this tissue results in various oral complications and decreased quality of life (QOL). In the current study, mice treated with targeted head and neck radiation showed a significant increase in double-stranded breaks (DSB) in the DNA of parotid salivary gland cells immediately after treatment, and this remained elevated 3 h posttreatment. In contrast, mice pretreated with insulin-like growth factor-1 (IGF-1) showed resolution of the same amount of initial DNA damage by 3 h posttreatment. At acute time points (30 min to 2 h), irradiated parotid glands had significantly decreased levels of the histone deactylase Sirtuin-1 (SirT-1) which has been previously shown to function in DNA repair. Pretreatment with IGF-1 increased SirT-1 protein levels and increased deacetylation of SirT-1 targets involved in DNA repair. Pharmacological inhibition of SirT-1 activity decreased the IGF-1-mediated resolution of DSB. These data suggest that IGF-1 promotes DNA repair in irradiated parotid glands through the maintenance and activation of SirT-1.