Laura Spruill

Differentiation of cardiac Purkinje fibers requires precise spatiotemporal regulation of Nkx2‐5 expression

Nkx2‐5 gene mutations cause cardiac abnormalities, including deficits of function in the atrioventricular conduction system (AVCS). In the chick, Nkx2‐5 is elevated in Purkinje fiber AVCS cells relative to working cardiomyocytes. Here, we show that Nkx2‐5 expression rises to a peak as Purkinje fibers progressively differentiate. To disrupt this pattern, we overexpressed Nkx2‐5 from embryonic day 10, as Purkinje fibers are recruited within developing chick hearts. Overexpression of Nkx2‐5 caused inhibition of slow tonic myosin heavy chain protein (sMHC), a late Purkinje fiber marker but did not affect Cx40 levels. Working cardiomyocytes overexpressing Nkx2‐5 in these hearts ectopically up‐regulated Cx40 but not sMHC. Isolated embryonic cardiomyocytes overexpressing Nkx2‐5 also displayed increased Cx40 and suppressed sMHC. By contrast, overexpression of a human NKX2‐5 mutant did not effect these markers in vivo or in vitro, suggesting one possible mechanism for clinical phenotypes. We conclude that a prerequisite for normal Purkinje fiber maturation is precise regulation of Nkx2‐5 levels. Developmental Dynamics 235:38–49, 2006.

Inflammasomes are important mediators of cyclophosphamide-induced bladder inflammation

Bladder inflammation (cystitis) underlies numerous bladder pathologies and is elicited by a plethora of agents such as urinary tract infections, bladder outlet obstruction, chemotherapies, and catheters. Pattern recognition receptors [Toll-like receptors (TLRs) and Nod-like receptors (NLRs)] that recognize pathogen- and/or damage-associated molecular patterns (PAMPs and/or DAMPs, respectively) are key components of the innate immune system that coordinates the production (TLRs) and maturation (NLRs) of proinflammatory IL-1β. Despite multiple studies of TLRs in the bladder, none have investigated NLRs beyond one small survey. We now demonstrate that NLRP3 and NLRC4, and their binding partners apoptosis-associated speck-like protein containing a COOH-terminal caspase recruitment domain (ASC) and NLR family apoptosis inhibitory protein (NAIP), are expressed in the bladder and localized predominantly to the urothelia. Activated NLRs form inflammasomes that activate caspase-1. Placement of a NLRP3- or NLRC4-activating PAMP or NLRP3-activating DAMPs into the lumen of the bladder stimulated caspase-1 activity. To investigate inflammasomes in vivo, we induced cystitis with cyclophosphamide (CP, 150 mg/kg ip) in the presence or absence of the inflammasome inhibitor glyburide. Glyburide completely blocked CP-induced activation of caspase-1 and the production of IL-1β at 4 h. At 24 h, glyburide reduced two markers of inflammation by 30-50% and reversed much of the inflammatory morphology. Furthermore, glyburide reversed changes in bladder physiology (cystometry) induced by CP. In conclusion, NLRs/inflammasomes are present in the bladder urothelia and respond to DAMPs and PAMPs, whereas NLRP3 inhibition blocks bladder dysfunction in the CP model. The coordinated response of NLRs and TLRs in the urothelia represents a first-line innate defense that may provide an important target for pharmacological intervention.

AGE Metabolites: A Biomarker Linked to Cancer Disparity?

Socioeconomic and environmental influences are established factors promoting cancer disparity, but the contribution of biologic factors is not clear. We report a mechanistic link between carbohydrate-derived metabolites and cancer that may provide a biologic consequence of established factors of cancer disparity. Glycation is the nonenzymatic glycosylation of carbohydrates to macromolecules, which produces reactive metabolites called advanced glycation end products (AGE). A sedentary lifestyle and poor diet all promote disease and the AGE accumulation pool in our bodies and also increase cancer risk. We examined AGE metabolites in clinical specimens of African American and European American patients with prostate cancer and found a higher AGE concentration in these specimens among African American patients when compared with European American patients. Elevated AGE levels corresponded with expression of the receptor for AGE (RAGE or AGER). We show that AGE-mediated increases in cancer-associated processes are dependent upon RAGE. Aberrant AGE accumulation may represent a metabolic susceptibility difference that contributes to cancer disparity. Cancer Epidemiol Biomarkers Prev; 23(10); 2186–91. ©2014 AACR.

A novel urodynamic model for lower urinary tract assessment in awake rats

To develop a urodynamic model incorporating external urethral sphincter (EUS) electromyography (EMG) in awake rats.

Liposarcoma of the head and neck: Analysis of 318 cases with comparison to non–head and neck sites

Liposarcomas are rare in the head and neck. We analyzed a large series of head and neck liposarcomas to determine features unique to the head and neck.

Regulation of c-jun mRNA expression in adult cardiocytes by MAP kinase interacting kinase-1 (MNK1)

Hypertrophic growth of adult myocardium is associated with increased expression of theearly response gene c‐jun. The purpose of this study was to determine whether eukaryotic initiation factor (elF)4E (eIF4E) regulates translational efficiency of c‐jun mRNA as measured by flux into polysomes. Adult feline cardiomyocytes in primary culture were treated with 0.2 µM 12‐O‐tetradecanoylphorbol 13‐acetate (TPA), and c‐jun mRNA was quantified in total, monosome, andpolysome fractions by real‐time polymerase chain reaction. After 1 h, TPA increased total c‐jun mRNA by 10.5‐fold. The corresponding flux into polysomes was significantly lower (5‐fold). Adenoviral‐mediated overexpression of either eIF4E or a nonphosphorylatable mutant (S209/A) did not affect total c‐jun mRNA or its flux between monosomes and polysomes. Similar results were obtained following overexpression of the eIF4E kinase Mnk1. Thus, translational efficiency of c‐jun mRNA was not affected by changes in activity ore amount of eIF4E. In contrast, a kinase‐deficient Mnk1 mutant significantly reduced total c‐jun mRNA from 9.8‐fold to 6.0‐fold while flux between monosomes and polysomes remained constant. The decrease in total c‐jun mRNA resulted from increased decay of c‐jun mRNA incorporated into the polysomes. We conclude that Mnk1 activity stabilizes c‐jun mRNA in polysomes independent of eIF4E phosphorylation. ‐Spruill, L. McDermott, P. Regulation of c‐jun mRNA expression in adult cardiocytes by MAP kinase interacting kinase‐1 (MNK1). FASEB J. 20, E1465‐E1475 (2006)

Severe hypercalcemia associated with uterine leiomyoma in pregnancy.

BACKGROUND: Uterine leiomyomas are the most common pelvic tumor, and a frequent indication of the need for gynecologic surgery. Although usually asymptomatic, life-threatening cases can occur. We present a case of critical hypercalcemia associated with a leiomyoma during pregnancy with the intention of highlighting the endocrinology of leiomyomas, features shared with malignant neoplasms, and the potential for effects on obstetric outcomes. CASE: A 32-year-old gravid woman with a large leiomyoma presented at 33 5/7 weeks of gestation with critical hypercalcemia requiring intensive care. Postpartum myomectomy cured her hypercalcemia, which was driven by parathyroid hormone-related protein (PTHrP) produced by the tumor. CONCLUSION: Obstetricians should be aware of the existence of humoral hypercalcemia related to leiomyomas and the potential effects on pregnancy.

Role of the 5′-untranslated region in regulating translational efficiency of specific mRNAs in adult cardiocytes

It has been hypothesized that translational efficiency is determined by the amount of secondary structure in the 5′‐untranslated region (5′‐UTR) of mRNA. Here, we examined whether specific 5′‐UTRs with excessive secondary structure selectively regulate translational efficiency in adult cardiocytes. Recombinant adenoviruses were generated to express reporter mRNAs consisting of the 5′‐UTR derived from c‐jun or ornithine decarboxylase (ODC) fused to β‐galactosidase (βGal) coding sequence. Each adenovirus expressed GFP mRNA as a control for 5′‐UTRs with minimal secondary structure. Subsequently, cardiocytes were electrically stimulated to contract at 1 Hz to accelerate protein synthesis as compared to quiescent controls. Translational efficiency was calculated by measuring protein expression as a function of mRNA levels. Translational efficiency of c‐jun/βGal mRNA increased significantly by 3.7‐fold in contracting vs. quiescent cardiocytes, but ODC/βGal mRNA was unchanged. Contraction increased c‐jun/βGal mRNAlevels in polyribosomes by 2.3‐fold, which indicates that translational efficiency was enhanced by mobilization. A short, unstructured 5′‐UTR was sufficient for efficient translation of βGal mRNA in quiescent and contracting cardiocytes. GFP mRNA produced similar results. These studies demonstrate that the 5′‐UTR functions as a determinant of translational efficiency of specific mRNAs, such as c‐jun, that regulate growth of the adult cardiocyte.—Spruill, L. S., McDermott, P. J. Role of the 5′‐untranslated region in regulating translational efficiency of specific mRNAs in adult cardiocytes. FASEB J. 23, 2879–2887 (2009). www.fasebj.org

Benign mimickers of malignant breast lesions.

Breast pathology is filled with pitfalls, including underdiagnosis of bland-appearing lesions, both invasive and non-invasive, misdiagnosis of malignant lesions as belonging to the wrong subgroup, for example, calling LCIS as DCIS or missing the metaplastic component of an invasive lesion, and overdiagnosis of benign lesions as malignancy. While each is a sin of varying severity, the overdiagnosis of benign lesions can be the most scarring, especially in this age where Angelina Jolie׳s prophylactic mastectomy is the headline news and patients are pushing for aggressive preventive treatment. In this review, we will consider some of the more common benign lesions and the malignant counterpart that they mimic, with the goal of identifying characteristic features that will lead to the correct diagnosis. Much of the discussions will center around the assessment of core biopsies, as smaller tissue volume is most often contributory to overcalling benign lesions.

Assessing the Relationship of Mammographic Breast Density and Proliferative Breast Disease

Increased breast density and a history of benign breast biopsy are both considered risk factors for developing breast cancer. Understanding the specifics of these risk factors and their relationship to each other can lead to a better understanding of a patients propensity for breast cancer development and improved surveillance strategies. We included 245 women who underwent a benign breast biopsy without atypia between October 2011 and June 2013. Biopsies were performed for suspicious calcifications as well as masses and architectural distortion. Lesions biopsied were divided into two groups: calcified and noncalcified lesions. The patients breast density was assessed on most recent mammogram and was classified using the American College of Radiology BI‐RADS density categories. Based on histologic diagnosis, each case was classified as proliferative or nonproliferative breast disease. The median age of the cohort (n = 245) was 55 years (range, 40–84 years). There were 162 (66%) postmenopausal women in the study. A core biopsy was performed for calcifications in 33.5% cases and for noncalcified lesions in 58% cases. In patients with dense breast tissue, an underlying proliferative histology was found significantly more frequently with calcifications (66.7%) as opposed to noncalcified lesions (35.9%) (RR = 2.3 (1.3–4.0); χ2 = 8.7; p = 0.003). In nondense breast patients, there was no significant difference (RR = 1.1 (0.7–1.8); χ2 = 0.1; p = 0.738). In the postmenopausal group, women with dense breasts had proliferative histology significantly more frequently than women with nondense breasts (55.3% versus 38.3%; p < 0.05), regardless of the underlying lesion type. Postmenopausal women with dense breasts who underwent a breast biopsy with benign histology had a significantly higher likelihood of having proliferative breast disease, regardless of underlying lesion type. Women with dense breasts also showed proliferative histology significantly more often for calcifications as opposed to noncalcified lesions.