Enterohemorrhagic Escherichia coli (EHEC) colonizes the intestine and produces the phage-encoded Shiga toxin (Stx) which is absorbed systemically and can lead to hemolytic uremic syndrome (HUS) characterized by hemolytic anemia, thrombocytopenia, and renal failure. EHEC, and two related pathogens, Enteropathogenic E. coli (EPEC), and the murine pathogen, Citrobacter rodentium, are attaching and effacing (AE) pathogens that intimately adhere to enterocytes and form actin “pedestals” beneath bound bacteria. The actin pedestal, because it is a unique characteristic of AE pathogens, has been the subject of intense study for over 20 years. Investigations into the mechanism of pedestal formation have revealed that to generate AE lesions, EHEC injects the type III effector, Tir, into mammalian cells, which functions as a receptor for the bacterial adhesin intimin. Tir-intimin binding then triggers a signaling cascade leading to pedestal formation. In spite of these mechanistic insights, the role of intimin and pedestal formation in EHEC disease remains unclear, in part because of the paucity of murine models for EHEC infection. We found that the pathogenic significance of EHEC Stx, Tir, and intimin, as well as the actin assembly triggered by the interaction of the latter two factors, could be productively assessed during murine infection by recombinant C. rodentium expressing EHEC virulence factors. Here we show that EHEC intimin was able to promote colonization of C. rodentium in conventional mice. Additionally, previous in vitro data indicates that intimin may have also function in a Tir-independent manner, and we revealed this function using streptomycin pre-treated mice. Lastly, using a toxigenic C. rodentium strain, we assessed the function of pedestal formation mediated by Tir-intimin interaction and found that Tir-mediated actin polymerization promoted mucosal colonization and a systemic Stx-mediated disease that shares several key features with human HUS.

Chronic kidney disease (CKD) progresses faster in males than females; however, the underlying mechanisms remain poorly understood. Sex differences in glomerular capillary morphology has been hypothesized to contribute, in part, to the increased susceptibility to hypertension-induced renal injury and CKD progression in males, but this has not been investigated. The goal of the present study was to assess glomerular capillary morphology in male vs. female rats with intact kidneys and after uninephrectomy (UNX). We hypothesized that glomerular capillary radii (RCAP) and length (LCAP) would be greater in male rats. Male (n=4) and female (n=4) with intact kidneys and UNX (n=4 males, n=4 females) provided a 0.4% NaCl diet and water ad libitum. Kidneys were perfusion-fixed, the left kidney was excised, and a 3 mm transverse section through the midline of the kidney was selected for further processing. Multiple 1 mm3 cubes were randomly excised from the left, middle, and right regions of the outer cortex, embedded in EPONTM, sectioned (1 μm), and stained with toluidine blue. Four glomeruli from each region were randomly selected for stereological analysis. Glomerular tuft volume (VG), RCAP, and LCAP were assessed. In rats with intact kidneys, no significant sex differences were observed in VG, RCAP, or LCAP. VG, RCAP, and LCAP were significant greater in both male and female rats with UNX vs. respective rats with intact kidneys. In rats with UNX, males exhibited a significantly greater VG and LCAP, but not RCAP, as compared to females despite no significant differences in relative kidney weight. These data indicate that males exhibit greater compensatory increases in LCAP following UNX. The greater capillary length may lead to reduced podocyte density, a well-known mechanism that increases the susceptibility to CKD progression.

Chlamydia trachomatis is the most prevalent agent of bacterial sexually transmitted infections in the world. However, a profuse number of cases are unreported, as the infection is often asymptomatic. Sequelae such as pelvic inflammatory disease, an increased risk of cervical cancer, premature birth, and perinatal infections in pregnant women can occur. Inflammation occurs in the body in response to infection or injury. Although inflammation can lead to some unwanted secondary effects, such as pain, it serves to return the body to homeostasis by restoring injured tissues and eliminating pathogens. One recently identified connection between the central nervous system and the immune system that regulates inflammation is the cholinergic anti-inflammatory pathway (CAP). In the CAP, pathogen-associated molecular patterns stimulate the vagus nerve to activate the pathway, which ultimately results in acetylcholine (ACh) release, which down regulates inflammation. We hypothesized that genital chlamydial infection would increase the expression of choline acetyltransferase (ChAT), the enzyme that synthesizes ACh, in the female murine genital tract, therefore down regulating inflammation and promoting chlamydial infection. Transgenic female mice carrying a ChAT-promoter driven GFP reporter gene were vaginally infected with C. muridarum. Mice were sacrificed on days 3, 9, 15, and 21 post infection; cervical, uterine horn, and ovarian tissues were removed and embedded in paraffin. Small sections of each tissue were cut and mounted onto slides. The tissue sections were then stained for the expression of ChAT using immunohistochemical techniques. Finally, tissue sections were viewed under a microscope for positive staining and the data was analyzed. The results indicated that there is a significant increase in the number of cells that express ChAT in genital tract of chlamydia-infected mice versus non-infected mice.

Equine arteritis virus (EAV) has a global impact on the equine industry being the causative agent of equine viral arteritis (EVA), a reproductive, respiratory, and systemic disease of equids. A distinctive feature of EAV infection is that it establishes long-term persistent infection in the reproductive tract of stallions and is continuously shed in the semen (carrier state). Recent studies showed that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S). However, the cellular and molecular mechanisms underlying the establishment and maintenance of persistent infection are yet to be determined. The studies were undertaken herein unequivocally demonstrated that the ampulla is the main EAV tissue reservoir rather than immunologically privileged tissues (i.e., testes) and that EAV has specific tropism for stromal cells and CD8+ T and CD21+ B lymphocytes but not glandular epithelium in the reproductive tract. Furthermore, persistent EAV infection is associated with a significant humoral, mucosal antibody and inflammatory response at the site of persistence, characterized by induction of high levels of neutralizing antibodies (IgG1), mucosal anti-EAV-specific IgA, IgG1, IgG3/5, and IgG4/7 with variable neutralizing efficacy; and moderate, multifocal lymphoplasmacytic ampullitis, with significant infiltration of T lymphocytes (mainly CD8+ and low numbers of FOXP3+ lymphocytes), CD21+ B lymphocytes, diverse Ig-secreting plasma cells, and Iba-1+ and CD83+ tissue macrophages/dendritic cells. Moreover, EAV long-term persistent infection is associated with a CD8+ T lymphocyte transcriptional profile with upregulation of T-cell exhaustion-related transcripts and homing chemokines/chemokine receptors (CXCL9-11/CXCR3 and CXCL16/CXCR6), orchestrated by a specific subset of transcription factors (EOMES, PRDM1, BATF, NFATC2, STAT1, IRF1, TBX21), which are associated with the presence of the susceptibility allele (CXCL16S). Finally, these studies have determined that long-term EAV persistence is associated with the downregulation of a specific seminal exosome-associated miRNA (eca-mir-128) along with an enhanced expression of CXCL16 in the reproductive tract, a putative target of eca-mir-128. These findings provide evidence that this miRNA plays a crucial role in the regulation of the CXCL16/CXCR6 axis in the reproductive tract of persistently infected stallions, a chemokine axis strongly implicated in EAV persistence. The findings presented herein suggest that complex host-pathogen interactions shape the outcome of EAV infection in the stallion and that EAV employs complex immune evasion mechanisms favoring persistence in the reproductive tract. Further studies to identify specific mechanisms mediating the modulation of the CXCL16/CXCR6 axis and viral immune evasion in the reproductive tract of the EAV long-term carrier stallion are warranted.

Background: The Veterans Health Administration (VHA) encourages depression screening and treatment for pregnant veterans; however, rates of depression symptoms and treatment utilization during pregnancy have not been well-studied. Methods: We used data from the Maternity Care Coordination for Women Veterans cohort study. Specifically, our aims were to: 1) examine rates and correlates of depression symptoms in a sample of pregnant veterans; 2) understand mental health care treatment utilization and explore the experiences of veterans accessing mental health care at the VHA during pregnancy; and 3) examine VHA mental health provider's perspectives on depression screening and treatment in the perinatal period. Findings: Depression symptoms were present in 28% of pregnant veterans in our sample. Social support and employment decreased odds of symptoms; history of anxiety, antidepressant use, and active duty service resulted in increased odds of symptoms. Nearly 70% of women veterans with prenatal depression symptoms received at least one mental health visit or antidepressant prescription during pregnancy. However, symptomatic pregnant women without a history of depression were less likely to receive care. Mental health providers identified absence of screening protocols and referral procedures and variability in risk/benefit conversations surrounding antidepressant use as areas of weakness for VHA mental health care during the perinatal period. Conclusions: Depression symptoms were present in nearly one in every three pregnant veterans. Depression treatment during pregnancy is complex, requiring individualized care. Policies for depression screening, referrals to providers, and medication review could be better encouraged to improve standardized care across the VHA.

Background: One in ten people in the U.S. are affected by a substance use disorder (SUD), roughly one third of whom are women. Rates of unintended pregnancy are higher in this population than in the general public. Little is understood about how women with SUD use prescription contraception and think about pregnancy. Methods: By analyzing Medicaid claims data and conducting qualitative interviews with women with SUD, this doctoral thesis seeks to: 1) compare any use of and consistent, continued coverage by prescription contraceptives between women with and without SUD; 2) determine the extent to which SUD is associated with pregnancy, abortion, and adverse feto-maternal outcomes in women who use prescription contraception; and 3) explore facilitators of and barriers to contraceptive utilization by women with SUD, using qualitative interviews. Results: Compared to women without SUD, women with SUD are less likely to use any prescription contraceptive, particularly long-acting reversible methods. Among women who do use long-acting methods, SUD is associated with less continued, consistent coverage by a prescription contraceptive. Among women who use contraception, SUD is also associated with increased odds of abortion. When interviewed, women with SUD report fatalistic attitudes towards pregnancy planning, and have difficulty conceptualizing how susceptibility to pregnancy may change over time. Women with SUD also report that pregnancy has substantial impact on their drug treatment prospects. Conclusions: This study is the first to examine contraceptive utilization by women with SUD who are enrolled in Medicaid or state-subsidized insurance. Our study may help to inform clinical practice and policy development to improve the reproductive health and wellbeing of women with SUD.

Background: Migraine headache is a chronic pain condition that affects 20% of women of reproductive age, and is often treated with triptans. Triptans are serotonin 1B, 1D, and 1F receptor agonists that act as vasoconstrictors and inhibitors of the trigeminal cervical complex as well as peripheral neurons; they cross the blood brain barrier and placenta, and as such are plausible neurodevelopmental teratogens. No studies have examined risk of neurodevelopmental problems in children with prenatal triptan exposure. This dissertation had three aims: (1) to examine risk of behavioral problems in children using in the presence of time-varying confounding by concomitant medication use; (2) to examine risk of temperamental, motor, and communication disturbances associated with prenatal triptans exposure, adjusting for unmeasured confounding by migraine type and severity; and (3) to examine changes in neurodevelopment over time associated with prenatal triptan exposure. Methods: This dissertation used data from the Norwegian Mother and Child Cohort Study, a prospective birth cohort including more than 100,000 women recruited during their first prenatal ultrasound visit. Aims 1 and 3 used marginal structural models to assess the risk of (1) neurodevelopmental problems at age 36 months (Aim 1), or (2) change in risk of neurodevelopmental problems from 18 to 36 months (Aim 3) associated with prenatal triptan exposure. Aim 2 used propensity matching and calibration to adjust for unmeasured confounding by migraine type, severity, and attitudes towards medication use in pregnancy. Neurodevelopmental outcome measures included the Child Behavior Checklist (CBCL), the Emotionality, Activity, and Temperament Scale (EAS), and the Ages and Stages Questionnaire (ASQ). Exposure to triptans was ascertained by self-report. Results: Prenatal triptan exposure was associated with greater externalizing behavior problems at 18 and 36 months, as well as greater increases in emotionality and activity from 18 to 36 months. We observed no association between triptan exposure and motor skills or communication problems; triptan use during pregnancy was associated with migraine severity but not migraine type, and adjustment for unmeasured migraine characteristics moved effect estimates towards the null. Conclusions: Prenatal triptan exposure is associated with externalizing-type behaviors and temperament in children, while migraine itself is associated with internalizing-type behaviors and temperament. The use of concomitant medications and the severity of the underlying condition both exerted substantial influence on observed effect estimates, and should be considered in any future studies of triptan medication use in pregnancy.

Chlamydia trachomatis is the most common sexually transmitted bacterial disease agent worldwide, and, though frequently asymptomatic, can cause extreme pathology including infertility. Chlamydial species exhibit a unique biphasic developmental cycle. Once attached to a cell surface, infectious elementary bodies (EB) are internalized within an inclusion, the membrane-bound structure in which EB transform to noninfectious, replicable reticulate bodies (RB). After multiple rounds of division, RB condense to form EB, which are released and can infect new host cells. In culture, exposure to stressors, such as beta-lactam antibiotics, induce chlamydiae to reversibly detour from normal development into a noninfectious, viable state termed persistence. Cell culture data suggest that persistent forms are resistant to azithromycin (AZM), a front-line antibiotic, and are able to alter the host transcriptome. Though persistence has been described in culture for over 50 years, whether or not it: i) occurs in vivo; and ii) influences chlamydial pathogenesis, transmission and therapy has remained unresolved. To address these questions, we developed an animal model of persistent chlamydial infection using amoxicillin (AMX) treatment. AMX exposure decreased shedding of infectious chlamydiae in C. muridarum-infected mice without affecting chlamydial viability, demonstrating the presence of persistent chlamydiae. Shedding of infectious EB resumed following AMX cessation. Shedding data and microarray analyses suggested that host immunity might limit chlamydia’s exit from persistence in our model. Thus, we hypothesized that cyclophosphamide (CTX) treatment would increase the magnitude of chlamydial shedding observed after AMX-treatment cessation. CTX treatment increased post-AMX shedding by more than 10-fold compared to AMX-only controls. To determine whether persistent chlamydiae are resistant to antibiotic eradication in vivo, we induced persistence by administering AMX and treated mice with various AZM dosing regimes. Persistently infected mice demonstrated increased treatment failure following AZM therapy compared to productively infected controls. These data suggest that persistent chlamydiae are refractory to treatment in vivo and provide an explanation for the observation that treatment fails in some patients. In addition to creating the first fully characterized, experimentally tractable, in vivo model of chlamydial persistence, these experiments provide evidence that persistent/stressed chlamydial forms may serve as a long-term reservoir of infectious organisms in vivo.