• Large Scale Gene Expression Analysis Reveals Insight into Pathways Related to Type 1 Diabetes and Associated Complications

      Carey, Colleen M.; Center for Biotechnology and Genomic Medicine (2013-08)
      Type 1 Diabetes (T1D) is a chronic inflammatory disease resulting from complex interactions between susceptibility genes, the environment, and the immune system, ultimately leading to the destruction o f pancreatic islet cells and insulin deficiency. Previous studies have examined the series o f molecular, cellular, and protein changes occurring within subsets of individuals and how these are associated with particular disease states. Genome wide association studies have revealed a large number o f genetic susceptibility intervals including those implicated in disease pathogenesis, the identification o f various markers for risk assessment, the classification o f disease or complications, and finally markers for monitoring therapies for disease. However, none of these studies to date is without seriously limitations. First, although microarray based gene expression profiling is a powerful tool in discovery; results must be validated by alternate techniques. Second, due to the inherent heterogeneity of the human population large sample sizes in each group must be used in order to handle the expected large expression variations among individual subject. Third, for accurate normalization of Real-Time PCR expression data appropriate reference genes must be selected. We proposed a large scale gene expression validation study to address the limitations of previous studies. Validation studies were performed using high throughput Real-Time RT-PCR on peripheral blood mononuclear cells (PBMCs) o f 928 individuals with T1D and 922 individuals as antibody negative (AbN) controls, recruited through the Prospective Assessment in Newborns of Diabetes Autoimmunity (PANDA) study. This dissertation work validated the gene expression changes among 28 genes shown to have differential expression in T1D patients as compared to controls. These genes were selected based on their function, role in inflammatory or the immune response, and any previously documented reference to a role in T1D. Our aims were to 1) identify gene expression changes which may be occurring specifically in diabetic complications, and 2) identify gene expression changes which may result in an increased state o f oxidative stress in the diabetic state. For validation studies, we divided the 28 genes into two subsets based on related function to ask whether any gene expression signatures could be associated with diabetes, diabetic complications, or oxidative stress in the diabetic state. Our studies revealed genes that are involved in inflammation, immune regulation, and antigen processing and presentation are significantly altered in the PBMCs o f T1D patients. Eight genes (S100A8, S100A9, MNDA, SELL, TGFB1, PSMB3, CD74, and IL12A) were shown to have higher expression, with three genes (GNLY, PSMA4, and SMAD7) having lower expression, in T1D when compared to controls. The data also suggested that inflammatory mediators secreted mainly by myeloid cells are implicated in T1D and its complications (Odds ratios OR = 1.3-2.6, adjusted P value= 0.005- 1.08 x 10 8), and particularly in those patients with nephropathy (OR=4.8-7.9, adjusted P value < 0.005). Validation studies also revealed nine genes (LAT2, MAPK1, APOBEC3B, SOD2, NDUFB3, STK40, PRKD2, ITGB2, and COX7B) with higher expression in T1D. These genes are involved in general pathways of inflammation and immune response; however SOD2, NDUFB3, and COX7B (OR=l.l-1.27, adjusted P value= 0.007-0.47) are functionally involved in the mechanisms o f the mitochondria and may play a role in the increased state of oxidative stress seen in T1D. In these studies we have validated and confirmed the gene expression differences between T1D and control subjects initially suggested by microarray. Our experimental design has addressed each of the limitations posed by earlier studies in the largest scale study to date on gene expression profiles in human T1D. We have demonstrated that gene expression is significantly different between autoantibody negative (AbN) controls and T1D patients without any complications. Genes implicated in immune function (S100A8, S100A9, MNDA, IL12A), immune regulation and promotion (TGFB1, SELL), antigen processing and presentation (CD74, PSMB3), and mitochondrial function (SOD2, NDUFB3, COX7B) have higher expression in T1D and support the notion that chronic inflammation and cellular oxidative stress contribute to the development of T1D and associated complications. The understanding gained from our results implies a translational potential for the use o f gene expression profiles in the classification o f at risk individuals for both T1D and complication. Further, our understanding into the role that the immune system plays in cellular oxidative stress leading to the diabetic state may serve to provide prevention therapies however there remains much to be learned before this is attainable.
    • Leveraging Medical Simulation to Teach Interprofessional Education (IPE): A Pilot Study

      Hernlen, Kathleen; Department of Advanced Studies and Innovation (Augusta University, 2019-05)
      Interprofessional education (IPE) is a term used to describe an educational technique that involves two or more learners from various professions learning from each other and with each other to increase collaboration among the learners and improve health care for their patients. Medical simulation can be described as any type of aid that can simulate a technique that is used in a clinical setting. The goal of this pilot study was to develop, implement, and evaluate an IPE medical simulation faculty training program that employed an IPE teaching method using the example of medical simulation which was lacking on the health sciences campus. A mixed methods study was developed to explore whether medical simulation could be used as a delivery method for an effective IPE faculty training program, and the extent to which IPE knowledge and perceptions changed as a result. A pre- and post-survey was given to faculty participants to evaluate their knowledge and perceptions of IPE. Following the training, faculty participants participated in a focus group. Data analysis included coding of focus groups responses and consolidating the codes into themes, and statistical analysis of the pre- and post-survey data. The findings of the pilot study included a statistically significant increase in knowledge and perceptions of IPE by the participating faculty which was corroborated by the focus group responses.
    • Leveraging Medical Simulation to Teach Interprofessional Education: A Pilot Study

      Etheridge, Rebecca Johnson; Department of Advanced Studies and Innovation (Augusta University, 2019-05)
      Interprofessional education (IPE) is a term used to describe an educational technique that involves two or more learners from various professions learning from each other and with each other to increase collaboration among the learners and improve health care for their patients. Medical simulation can be described as any type of aid that can simulate a technique that is used in a clinical setting. The goal of this pilot study was to develop, implement, and evaluate an IPE medical simulation faculty training program that employed an IPE teaching method using the example of medical simulation which was lacking on the health sciences campus. A mixed methods study was developed to explore whether medical simulation could be used as a delivery method for an effective IPE faculty training program, and the extent to which IPE knowledge and perceptions changed as a result. A pre- and post-survey was given to faculty participants to evaluate their knowledge and perceptions of IPE. Following the training, faculty participants participated in a focus group. Data analysis included coding of focus groups responses and consolidating the codes into themes, and statistical analysis of the pre- and post-survey data. The findings of the pilot study included a statistically significant increase in knowledge and perceptions of IPE by the participating faculty which was corroborated by the focus group responses.
    • Life changes and perceived psychosocial implications for child victims and their families following disclosure of incest

      Stephenson, Grace H; School of Nursing (1987-01)
      This study addresses the ps-ychosocial implications of life changes occurring for children after disclo~ure of an incestuous relationship. Subjects ~ere 11 families obtained from the cas~load of .a county Depart~ent 6f Family and Child. Protective Services .. The· subjects w~re··f~male with ·a~e~ fr6m 5-17, black and white subjects we~e .. ~epr~sented. This was a descriptive study with data obtained from interviews with lawyers, therapists, mothers, and caseworkers. A content analysis approach was used for data analysis. Synthesis of the data revealed all families continued to experience turmoil yeats after the disclosure. Eleven categories. representing life changes were obtained from the data. The categories of famili di~ruption and"mother's inability t6 provide emotional support for her daughter were the most represented categorie~.
    • Macrophage Recruitment Signals Following Unilateral Chorda Tympani Nerve Degeneration

      Cavallin, Melissa Ann; Department of Neuroscience and Regenerative Medicine (2007-02)
      The chorda tympani nerve (CT) innervates taste buds within fungiform papillae. Unilateral transection of the CT causes degeneration of the ipsilateral taste buds and a bilateral increase in activated lingual macrophages. However, dietary Na+ restriction prevents the macrophage response and results in a subnormal neural response to Na+ stimuli by the contralateral, intact CT. Stimulating immune system function with lipopolysaccharide (LPS) restores the bilateral macrophage response to CT section in Na+-restricted rats. This macrophage response is associated with the recovery of normal taste function, suggesting that macrophages affect taste function. Intracellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, and monocyte chemoattractant protein (MCP)-1 are upregulated prior to and during the peak macrophage response suggesting that these molecules are recruitment signals for macrophage entry following CT injury. Macrophage inflammatory protein (MIP)-1α is not significantly upregulated following CT section. Importantly, the increase in VCAM-1 expression is prevented by dietary Na+ restriction, which may partially explain the decreased macrophage response in these animals. However, binding of an antibody against platelet endothelial cell adhesion molecule (PECAM)-1, which is downstream of ICAM-1 and VCAM-1, paradoxically increases macrophage recruitment and does not alter taste function. Other adhesion molecules may be able to compensate for the loss of PECAM-1. The response of the immune system to CT section is diverse and requires the cooperation of many molecules in order to recruit macrophages to maintain normal taste function. ICAM-1, VCAM-1, and MCP-1 are upstream recruitment signals for macrophages that may ultimately affect the function of taste receptor cells.
    • Maintenance of AR Inactivation by S-nitrosylation

      Qin, Yu; Department of Biochemistry and Molecular Biology (2011-04)
      Prostate cancer is the second leading cause of cancer deaths in US men. Unregulated activation of the androgen receptor (AR) is associated with prostate cancer initiation and progression. Post-translational modifications of AR regulate its function, and we propose that nitric oxide (NO) synthase III (eNOS) and its product NO regulate prostate cancer cell growth via S-nitrosylation, a covalent addition of an NO group to a cysteine thiol, of AR. We found that S-nitrosylation levels were reduced in prostate cancer and prostatic intraepithelial neoplasia compared to normal adjacent tissues, and xD;1089-8603 (Linking)15566968
    • Marker Co-Expression Analysis of Initial Cellular Events in the Critical-Size Rat Calvarial Defect Model and the Effect of Bone Morphogenetic Protein-2 (rhBMP-2)

      Capetillo, Joseph F.; Department of Oral Biology (4/15/2016)
      Craniofacial defects can result from congenital malformations, trauma, tumor resection,periodontal disease, post-extraction ridge remodeling, and peri-implantitis. Regenerationof bone is critical to achieving functional and esthetic outcomes in the rehabilitation ofsuch defects. Traditional strategies for osseous regeneration include a multiple ofsurgical techniques utilizing autologous bone, cadaver-sourced allogeneic or xenogeneicbone, synthetic bone biomaterials, barrier membranes, or combinations thereof(Wikesjö, Qahash 2009). The need to enhance the predictability of regeneration inespecially large defects that cannot heal adequately without intervention (critical-sizedefects) has led to recent development of protein- and cell-based technologies.[Introduction, first paragraph]
    • Marketing Emergency Services: The Degree of Involvement Among Nurse Executives

      Byrd, Lura A.; Department of Physiological and Technological Nursing (1986-05)
      The purpese of this study is to determine the degree of invo1vement among nurse executi~es i~ marketi~g emergency s~rvices. Know1edge ther~by obtained will provide identification of cu~rent marketing.trends in emergency services as wel.l as areas ofmarketing content in education programs preparing nurse executfves. A questionnaire~ 11Emergency Services Marketing Activity Survey 11 (ESMAS)~ specific for marketing e~ergency Services was ·adapted from Kotler•s (1975) 11 Systematic Marketing Audit. 11 Items were dev-eloped far·· each major category (marketing environment; marketing system; and ma·rketing activity}'. purported· by Kotler (1975) to be·essentia1 in eva1uating marketing activities. The ESMAS was reviewed by a panel of fie1d experts including facu1ty invo1ved in teaching marketing and finance in hea)th care services. Based on recommendations from the pane1, severa1 items were revised and made less ambiguous. The revi sed vers i on of the ESMAS Questi onna i re was ma i 1 e.9 to Di rectors of Nurs i.ng (DON) and Emergency Department Head Nurses ( EDHN) in 114 Georgia hospitals 1isted by the American Hospital Association Gui de (1985} as· provi ders of emergency servi ces. Study subj ects were asked to respond on a sca 1 e of one to 'seven to .the de·gree to whi eh each marketing emergency services item is a part of their role as nurse executive. Responses were received from 42 DONs and 37 EDHNs. Descriptive information was compi1ed and t-test analysis was done to describe the V involvement of DONs and EDHNs in marketing emergency services and to describe the relationship between the involvement of DONs and EDHNs in their marketing involvement. Involvement was divided into three categories: a rating 1.0-2.9 was considered low involvement, 3.0-4.9 wa? considered moderate involvement,_ and 5.0:7.0 was considered h1gh involvement~ It was·found that·nurses were involved in marketing overall at the moderate level·. There we~e significant differences at the 0.029 level in the involvement of DONs and EDHNs in marketing environment category. There were no significant differences between the involvement of the two groups in marketing system nor in marketing activities categories.
    • Marketing hospital based obstetrical services : the degree of involvement among nurse executives

      Watford, Deborah L.; Master of Science (1987-04)
      The purpose of this study was to determine the degree of involvement among obstetrical nurse executives in marketing hospital-based obstetrical (OB) services. A descriptive nonexperimental design was.used. The "Obstetrical Services Marketing Activity Survey" (OSMAS) and a "General Data Questionnaire" (GDQ) were administered to 90 Directors of Nursing (DONs) for OB Services and 90 Labor and Delivery Head Nurses (LDHNs) in 90 hospitals located in three southern states. The OSMAS was adapted for obstetrical services from an original, unpublished tool entitled "Emergency Services Marketing Activity Survey" (Byrd, 1986). Responses were received from 26 DONs and 23 LDHNs, representing a 27% return rate. On a scale of one to seven, marketing involvement was arbitrarily divided into three categories: 1.0 to .2.9 wa$ designated as a low level of involvement; 3.0 to 4.9 was designated as a moderate level of involve.ment; and 5. 0 to 7. 0 was designated as a high level of inv.olvement. The results of this study indicated that OB nurse executives overall were involved in marketing at the moderate level (4.86 mean). !-Test analysis revealed no significant differences at the .05.level in the degree of involvement bet~een LDHNs and DONs in marketing OB servic_es. Through descriptive analysis, it wa~ found that the health care industry, P.ar~icularly OB.services, is competitive in nature. It was concluded that OB nurse executives are becoming more involved in marketing their hospital-based OB departments~ yet they are not educationally prepared to engage in marketing activities.
    • Maternal-Fetal Bonding and A Previous Spontaneous Abortion

      Elkins, Sharon; Department of Nursing (1985-10)
      Maternal-Fetal Bonding and a Previous Spontaneous Abortion. Sharon Sue Elkins. The purpose of this study was to investigate the relationship between the occurrence of a spontaneous abortion in a prior pregnancy and maternal-fetal bonding· in a. current pregnancy. Cranley•s Maternal;;;Fetal Attachment Sca'le and a demographic questionnaire were completed by 236 pregnant women attending either Lamaze classes or a prenatal clinic .. There was no significant difference found in maternal-fetal bonding, measured by the total score on Cranley•s Maternal-Fetal Attachment Sea 1 e, between wome·n who had experienced a spontaneous abortion .in the previous_ pregnancy and women who had not experienced· a spontaneous abortion in the previous pregnancy. However, on ·subscale (2) 11 interaction with the fetus 11 the scores of the spontaneous abortion group. were significantly lower than the scores of the lnonspontaneous abortion group. A1 s o, the spontaneous abortion group had a significantly greater variance than the nonspontaneous abortion group. No relationship was found between the number of weeks pregnant at the time of the spontaneous abortion and maternal~fetal bonding. -. Social class was found to have the greatest effect on maternal-fetal bonding of all the observed variables. Women in higher social classes had significantly higher total scores on the Maternal-Fetal Attachment Scale. Also-, Caucasian women and younger women had significantly \higher total scores on the Maternal-Fetal Attachment Scale. Women who were the greater number of weeks pregnant also had significantly higher scores ·on two of the subscales, 11 i·nteraction with the fetus" and 11 giving of self ...
    • Mathematical and Stochastic Modeling of HIV Immunology and Epidemiology

      Lee, Tae Jin; Department of Biostatistics and Epidemiology (8/3/2017)
      In HIV virus dynamics, controlling of viral load and maintaining of CD4 value at a higher level are always primary goals for the providers. In recent years, a new molecule was discovered, namely, eCD4-Ig, which mimics CD4 if introduced into the human body and has potential to change existing HIV virus dynamics. Thus, to understand dynamics of viral load, eCD4-Ig, CD4 cells, we have developed mathematical models by incorporating interactions between this new molecule and other known immunological, virological information. We further investigated model based speculations for management, and obtained the level of eCD4-Ig required for elimination of virus. Next, we built epidemiological model for HIV spread and control among discordant couple through dynamics of PrEP (Pre-exposure prophylaxis). For this, an actuarial assumptions based stochastic model is used to obtain the mean remaining time of couple to stay as discordant. We generalized single hook-up/marriage stochastic model to multiple hook-up/marriage model.
    • The Meaning of Life in Organ Transplant Recipients

      Jonason, Anna M.; Department of Physiological and Technological Nursing (1993-05)
      The purpose of this study was to explicate the meaning of life as experienced in a population of renal, cardiac, and liver transplant recipients. The method used was two-fold: A phenomenological design to explore qualities of the lived experience in subjective terms. A questionnaire provided measurable information for corroboration and validation. The theoretical perspective of will to meaning (Frankl, 1969) served as a basis for the study. This view suggests that the search for personal meaning is a primary motivating force for continued survival in human beings. A convenience sample of eleven vital organ transplant recipients participated in the study. Initially, the Life Attitude Profile-Revised (LAP-R) (Reker, 1992) was completed by each participant. This is a multidimensional, Likert-type instrument measuring attitudes toward life. Questionnaire completion was followed by semi-structured interviews. The two sets of data were examined separately. Interviews were analyzed according to phenomenological guidelines set forth by van Kaam (1966), leading to structural definition of the meaning of life for organ transplant recipients. LAP-R data were then analyzed. Analysis culminated in a syncretic integration of findings from both data sources. This provided a rich, contextual description of the indomitability of the human spirit. The meaning of life for organ transplant recipients was a complexity of interconnected aspects, reflecting a paradox of emotions and great intensity. It was at once evolutionary and revolutionary, comedy and tragedy, struggle between dependence and independence, and dream tempered by reality. Important themes described included drawing on internal sources of strength; having the support of family and friends; a desire to help others; acknowledgement of the contributions of a "greater force" to continued survival; some semblance of inner peace; a need to achieve one's purpose in life; and a sense of renewed responsibility for oneself and one's health. Findings from this study afford new insights for clinical nursing. These insights are grounded in improved mutual understanding between persons, which is a critical element for efficient health care planning and effective intervention.
    • A Measure of Satisfaction in Childbirth: The Degree of Women's Fulfillment of Childbearing Expectations

      Cooke, Paulette A.; Department of Nursing (1984-03)
      The ·purpose of .this . study wa~ . to . operationalize the· coJ;icept of . . satisfactiqn (based on· Porter's model). as it pertained to the l~bor and . delivery experi~nce. - 'The goal was to develop and test a tool for measuring a _wo1Jlan' s ·satisfaction with chil_dbirth. in terms. of the difference·· between ~hat was expected .and what· actually occurred.. Satisfaction was . defined as the deg-ree to which expectations were met. A convenience_sample of 50 women from a u.·s. Army hospital . . ' . . participated in this· study_. Of .the saJJiple,_ 44%. (n = 22) were primigrav~das, . . _and 56%_ (n. ~ _28) were multigravidas. A descriptive design· -w~s used for_ reliability a')ld valid~ty estimates~·. The results- of conte~t validity indicated that 4ll of . 'the· itens were consid~red relevant for a measure .· of satisfac-tion with the chilQ.birth experience. There .was 84% agreement ·by experts ob··· item ·(n =-.. :46) .placem~nt into appropriate .subscales . (self, physical care, ·sup_port). The reliability_ coefficient. (Cro11bach' s Alpha) for the Cooke Satisfaction· Scale was • 89. For each subscale, the : reliabilit:J;es (alpha)· were: self,_ .48;, physical care,· .74.;.-and support, .8·6. ·The correlation .for the Cooke Satisfaction Scale (Part A) and the· Marui: and· Mercer Attitude· Scale ·for. convergent construct validity was · .53. The· correlation for, the Cooke Satisfaction Scale (Part A - Par-t ·B) with the Marut and Mercer Scale· for divergent construct. validity· was .1s-.~ On the basi~ of reliability_ and validity coefficients. obtained, it. was concluded that the Cooke Satisfaction Sc·ale is a usefui tool for the · measurement .of ·satisfaction in childl;»earirig .. women.

      Elmasry, Khaled; Department of Biochemistry and Molecular Biology / Cancer Center (5/22/2018)
      Our earlier studies have established the role of 12/15-lipoxygenase (LO) in mediating the inflammatory reaction in diabetic retinopathy. However, the exact mechanism is still unclear. The goal of the current study was to identify the potential role of endoplasmic reticulum (ER) stress as a major cellular stress response in the 12/15-LO-induced retinal changes in diabetic retinopathy. We used in vivo and in vitro approaches. For in vivo studies, experimental diabetes was induced in wild-type (WT) mice and 12/15-Lo (also known as Alox15) knockout mice (12/15-Lo−/−); ER stress was then evaluated after 12-14 weeks of diabetes. We also tested the effect of intravitreal injection of 12-hydroxyeicosatetraenoic acid (HETE) on retinal ER stress in WT mice and in mice lacking the catalytic subunit of NADPH oxidase, encoded by Nox2 (also known as Cybb) (Nox2−/− mice). In vitro studies were performed using human retinal endothelial cells (HRECs) treated with 15-HETE (0.1 µmol/l) or vehicle, with or without ER stress or NADPH oxidase inhibitors. This was followed by evaluation of ER stress response, NADPH oxidase expression/activity and the levels of phosphorylated vascular endothelial growth factor receptor-2 (p-VEGFR2) by western blotting and immunoprecipitation assays. Moreover, real-time imaging of intracellular calcium (Ca2+) release in HRECs treated with or without 15-HETE was performed using confocal microscopy. Deletion of 12/15-Lo significantly attenuated diabetes-induced ER stress in mouse retina. In vitro, 15-HETE upregulated ER stress markers such as phosphorylated RNA-dependent protein kinase-like ER-regulated kinase (p-PERK), activating transcription factor 6 (ATF6) and protein disulfide isomerase (PDI) in HRECs. Inhibition of ER stress reduced 15-HETE-induced-leukocyte adhesion, VEGFR2 phosphorylation and NADPH oxidase expression/activity. However, inhibition of NADPH oxidase or deletion of Nox2 had no effect on ER stress induced by the 12/15-LO-derived metabolites both in vitro and in vivo. We also found that 15-HETE increases the intracellular calcium in HRECs. ER stress contributes to 12/15-LO-induced retinal inflammation in diabetic retinopathy via activation of NADPH oxidase and VEGFR2. Perturbation of calcium homeostasis in the retina might also play a role in linking 12/15-LO to retinal ER stress and subsequent microvascular dysfunction in diabetic retinopathy.
    • The Mechanism of Monomethylfumarate (MMF) as an Anti-psoriatic Agent

      Helwa, Inas; Department of Physiology (2014-09)
      Psoriasis is a chronic hyperproliferative inflammatory skin disorder whose primary etiology is not well understood. Keratinocytes play a pivotal role in the pathogenesis of psoriasis. The fumaric acid ester monomethylfuamarate (MMF) is the bioactive ingredient of the anti-psoriatic drug Fumaderm©, licensed in Germany since 1994. However, the exact mechanism of action of MMF is not yet well understood. Our data showed that MMF dose-dependently inhibited proliferation in primary murine and human keratinocytes and significantly increased the protein expression of the early marker of differentiation K10 and the activity of the late marker of differentiation transglutaminase enzyme. In addition, MMF inhibited mRNA expression of IL-6, TNFα and IL-1α and inhibited the protein expression of TNFα. Recently, the role of oxidative stress in psoriasis etiology has evolved and MMF has been shown to stimulate Nrf2 and mediate its nuclear translocation in other cell types. Therefore, we examined the effect of MMF on Nrf2 expression, localization and downstream effectors in keratinocytes. Nrf2 protein expression and nuclear translocation significantly increased following MMF treatment. Moreover, MMF significantly increased the mRNA expression of the Nrf2- downstream anti-oxidative enzymes, heme oxygense-1 and peroxiredoxin-6. MMF also decreased ROS generation in keratinocytes. Aquporin3 (AQP3) is a glycerol channel expressed in keratinocytes. Earlier studies from our group as well as others have shown that AQP3 plays a role in inducing early keratinocyte differentiation and that the activity of AQP3 correlates with its membranous localization. Therefore, we examined the effect of MMF on AQP3 expression and localization. MMF increased the mRNA and protein 3 expression of AQP3. In addition, MMF stimulated membranous translocation of AQP3 and increased glycerol uptake by keratinocytes. Eventually, we wanted to examine whether Nrf2 plays a role in the expression of AQP3. Our data showed that the Nrf2 stimulator sulforaphane (SFN) increased the expression of AQP3. Thus, our data suggest that MMF exerts its action through Nrf2 stimulation. Nrf2 stimulation helps to regain keratinocyte oxidative balance and may also play a role in inducing AQP3 expression and activity. This provides the molecular basis for the MMF-mediated improvement of keratinocyte differentiation and inhibition of keratinocyte proliferation.
    • Mechanisms Driving Innate Regulation Of Immunological Tolerance To Apoptotic Cells Preventing Autoimmunity

      Shinde, Rahul; Department of Neuroscience and Regenerative Medicine (2015-08)
      Innate immune responses to apoptosis are crucial for self-tolerance. Although upstream signals promoting recognition and processing of apoptotic cells have been extensively studied, downstream molecular mechanisms driving innate regulation of apoptotic cell responses are less understood. Here we report an unsuspected discovery that the ligand dependent transcription factor aryl hydrocarbon receptor (AhR) initiates tolerogenic signaling to apoptotic cells and prevents systemic autoimmunity. AhR is known to control xenobiotic stress responses and recently has been linked to modulation of T cell and DC function. In this study, we found that apoptotic cells induced AhR signals in tissueresident MΦs and activation was dependent on DNA from apoptotic cells. AhR was required for apoptotic cell driven immune suppression as deletion of AhR abrogated IL-10, promoting the inflammatory cytokines IL-6 and IL-12, while supplementing IL-10 restored the regulatory phenotype of MΦs. Moreover, inhibition of the AhR pathway fundamentally altered immune responses to apoptotic cells resulting in proinflammatory cytokine production, increased effector T cell responses and abrogation of long-term allograft tolerance to apoptotic cell associated antigens. Further, mice lacking AhR developed spontaneous autoimmunity characterized by excessive macrophage and lymphocyte activation associated with renal pathology. Deficiency of AhR led to breakdown in tolerance with rapid increases in anti-dsDNA and anti-histone antibody responses after chronic challenge with apoptotic cells. Similarly, when SLE-prone mice were treated with AhR antagonist they exhibited significantly elevated humoral auto-reactivity, augmented inflammatory cytokine production in MΦs, intensified autoreactive B and T cells, renal pathology, and mortality; while AhR agonist treatment resulted in significant reduction of autoimmune disease parameters compared to control mice. Collectively, the data demonstrate apoptotic cell activation of AhR is a key mechanism suppressing anti-apoptotic cell inflammatory responses preventing autoimmunity.
    • Mechanisms for Control of Renal Vascular Resistance in Type 1 Diabetes Mellitus

      Bell, Tracy D.; Department of Physiology (2007-04)
      Glomerular hyperfiltration and an increase in renal blood flow are hallmark characteristics of Type I Diabetes Mellitus in the early stages, and are major risk factors for the development of diabetic nephropathy. Previous studies from our laboratory have implicated an important role for the Nitric Oxide system in mediating this response, because giving nitric oxide synthase inhibitors prevented the increase in renal plasma flow and glomerular filtration rate during diabetes. However, a limitation of these studies is that single point measurements were taken and may not reflect the time-dependent role of nitric oxide. Therefore, we have developed a more precise method to measure the role of nitric oxide in the chronic control of renal blood flow during diabetes. We measured renal blood flow continuously, 18 hr/day using a Transonic flow probe in control (C) and diabetic (D) rats. Renal blood flow averaged 8.0±0.1 and 7.8±0 ml/min in the C and D groups, respectively, during the control period and induction of diabetes caused a marked and progressive increase in renal blood flow in the D rats, averaging 10±6% above control on day 1, and 22±3% and 34±1% above control by the end of diabetes weeks 1 and 2. During the control period, glomerular filtration rate averaged 2.1 ±0.1 and 1.7±0.1 ml/min in the C= and D groups, respectively. Glomerular filtration rate did not change during the experiment in the C rats, but increased significantly in the D group, averaging 54±21 and 52±19% above control during diabetic weeks 1 and 2 and renal vascular resistance decreased significantly during the diabetic period. There were no significant changes in filtration fraction in either group. Importantly, chronic blockade of nitric oxide completely prevented the increase in renal blood flow and prevented the diabetes-induced hyperfiltration normally associated with diabetes. These data together suggest that nitric oxide is essential for the renal vasodilation caused by onset of type I diabetes and suggest that the renal vasodilation in diabetes occurs primarily at the afferent arteriole. Autoregulation of the afferent arteriole plays an important role in determining glomerular capillary hydrostatic pressure and glomerular filtration. In diabetes, renal autoregulation may be impaired, but the relative roles of myogenic and tubuloglomerular feedback mechanisms in controlling renal blood flow, and the time course of their involvement, is not known. In addition, there is very little known about autoregulatory mechanisms at the very onset of diabetes, before there has been time for renal structural changes to become manifest. Therefore, we designed experiments to establish the role of the myogenic response and tubuloglomerular feedback mechanism in renal blood flow control at the onset of diabetes. Coupling continuous measurement of renal blood flow using Transonic flow probes and continuous measurement of arterial pressure, we were able to use transfer function analysis to determine the relationship between arterial pressure and renal blood flow. This type of analysis examines the dynamic ability of the renal vasculature to attenuate, or autoregulate, the influence of the oscillatory power of blood pressure over the range of frequencies Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. at which the myogenic response and tubuloglomerular feedback mechanism operate. In these studies we demonstrated that transfer function gain was negative, indicating effective autoregulation, in the frequency range of the myogenic (0.1- 0.3 Hz) and tubuloglomerular feedback (0.03-0.06 Hz) mechanisms during control days. However, at the onset of diabetes gain increased to positive values and continued through the 2-week diabetic period. Chronic blockade of nitric oxide in diabetic rats normalized the increase in transfer function gain and possibly enhanced the autoregulatory response. Our model provides a novel method to measure the chronic effects of the nitric oxide on renal blood flow control during diabetes. By using this model we have demonstrated that nitric oxide is required for the immediate increase in renal blood flow in diabetes. Furthermore, these data suggest renal autoregulation is impaired at the onset of diabetes and may play a role in the increase in renal blood flow and glomerular filtration rate early in diabetes. In addition, these data together suggest that nitric oxide contributes to the impaired autoregulatory capacity of the renal vasculature.