Publications

The mechanism of AMP‐activated protein kinase (AMPK) activation in the ischemic heart remains poorly understood. Recent evidence implicates the role of Sestrin2 (Sesn2) in the AMPK signaling pathway and we hypothesize that Sesn2 plays an influential role during myocardial ischemia in order to promote AMPK activation. Sesn2 protein was found to be expressed in adult cardiomyocytes. Interestingly, Sesn2 was found to accumulate in the heart during ischemic conditions. Cardiac phenotype analysis of WT and Sesn2 KO mice were not significantly different. When subjected to in vivo ischemia/reperfusion (I/R), myocardial infarction was significantly greater in Sesn2 KO versus WT hearts. Similarly, Langendorff perfused hearts indicated exacerbated cardiac function after I/R injury in Sesn2 KO versus WT as evidenced by decreased LVDP, dP/dt, and rate‐pressure products. Moreover, ischemic AMPK activation was reduced in Sesn2 KO hearts. Immunoprecipitation of Sesn2 demonstrated an association with AMPK. Importantly, immunoprecipitation of LKB1 from WT hearts demonstrated AMPK association during ischemia while LKB1‐AMPK interaction in Sesn2 KO hearts was nearly abolished. The results demonstrate an important cardioprotective role of Sesn2 against I/R injury by acting as a LKB1‐AMPK scaffold.

We evaluated psychosocial, built-environmental, and policy-related correlates of adolescents' indoor tanning use.

Objectives To describe both conditions of a two-group randomized trial, one that promotes physical activity and one that promotes cancer screening, among churchgoing Latinas. The trial involves promotoras (community health workers) targeting multiple levels of the Ecological Model. This trial builds on formative and pilot research findings. Design Sixteen churches were randomly assigned to either the physical activity intervention or cancer screening comparison condition (approximately 27 women per church). In both conditions, promotoras from each church intervened at the individual- (e.g., beliefs), interpersonal- (e.g., social support), and environmental- (e.g., park features and access to health care) levels to affect change on target behaviors. Measurements The study’s primary outcome is min/wk of moderate-to-vigorous physical activity (MVPA) at baseline and 12 and 24months following implementation of intervention activities. We enrolled 436 Latinas (aged 18–65 years) who engaged in less than 250min/wk of MVPA at baseline as assessed by accelerometer, attended church at least four times per month, lived near their church, and did not have a health condition that could prevent them from participating in physical activity. Participants were asked to complete measures assessing physical activity and cancer screening as well as their correlates at 12- and 24-months. Summary Findings from the current study will address gaps in research by showing the long term effectiveness of multi-level faith-based interventions promoting physical activity and cancer screening among Latino communities.

Mice lacking p63, a single gene that encodes a group of transcription factors that either contain (TA) or lack (DeltaN) a transactivation domain, fail to develop stratified epithelia as well as epithelial appendages and limbs. DeltaNp63 isoforms are predominantly expressed during late embryonic and postnatal epidermal development, however, the function of these proteins remains elusive. Using an epidermal-specific inducible knockdown mouse model, we demonstrate that DeltaNp63 proteins are essential for maintaining basement membrane integrity and terminal differentiation of keratinocytes. Furthermore, we have identified two DeltaNp63alpha target genes that mediate these processes. We propose that DeltaNp63alpha initially induces expression of the extracellular matrix component Fras1, which is required for maintaining the integrity of the epidermal-dermal interface at the basement membrane. Subsequently, induction of IkappaB kinase-alpha by DeltaNp63alpha initiates epidermal terminal differentiation resulting in the formation of the spinous layer. Our data provide insights into the role of DeltaNp63alpha in epidermal morphogenesis and homeostasis, and may contribute to our understanding of the pathogenic mechanisms underlying disorders caused by p63 mutations.

Abstract Description NLRP3 inflammasome activation depends on stress-induced production of oxidized mitochondrial DNA (Ox-mtDNA) fragments that enter the cytoplasm to bind NLRP3 and activate caspase-1. Along with pro-IL-1b processing, caspase-1 generates gasdermin D pores that result in circulatory mtDNA release. Elevated amounts of circulating cell-free (ccf)-mtDNA, which is likely to be oxidized, were documented in the elderly and patients with metabolic and autoimmune disorders and its intra-articular injection elicited arthritis in mice. Investigating whether ccf-mtDNA may promote autoimmunity, we found that induction of sustained Ox-mtDNA release triggered by a prototypical NLRP3 inflammasome activator elicited autoantibody production and glomerulonephritis in mice. Similar autoimmune responses, dependent on plasmacytoid dendritic cells (pDC) and T follicular helper cells (Tfh), were elicited by in-vitro generated Ox-mtDNA but not by non-oxidized mtDNA. Although both mtDNA forms were internalized by pDC and induced interferon-a, only Ox-mtDNA stimulated autocrine IL-1β signaling that induced expression of immunoregulatory and co-stimulatory molecules, including IL-21, that enabled mouse and human pDC convert naïve CD4+ T cells into functional Tfh, supportive of autoantibody production. Highlighting pDC-generated IL-1β as an orchestrator of autoantibody production, these findings suggest that Ox-mtDNA could be a key participant in immune-aging and unravel new therapeutic opportunities. Funding Sources Arthritis National Research Foundation (#1291101); NIH grants R01 DK100640 and R37 AI043477 Topic Categories Basic Autoimmunity (BA)

Arsenite is a potent environmental toxin that causes various pathologies including cancers and skin disorders. Arsenite is believed to exert its biological effects through reaction with exposed sulfhydryl groups, especially pairs of adjacent thiols. Here, we describe the mechanism by which arsenite affects the NF-kappaB signaling pathway. Activation of transcription factor NF-kappaB depends on the integrity of the IkappaB kinase (IKK) complex. We found that arsenite potently inhibits NF-kappaB and IKK activation by binding to Cys-179 in the activation loop of the IKK catalytic subunits, IKKalpha/beta. The affinity of IKKbeta for trivalent arsenic was verified in vitro by the ability of IKKbeta to enhance the fluorescence of an arsenic-substituted fluorescein dye. The addition of 1,2-dithiol antidotes or replacement of Cys-179 with an alanine residue abolished dye binding to and arsenite inhibition of IKKbeta. Overexpression of IKKbeta (C179A) protects NF-kappaB from inhibition by arsenite, indicating that despite the involvement of a large number of distinct gene products in this activation pathway, the critical target for inhibition by arsenite is on the IKK catalytic subunits.

Sedentary behavior (SED) is a cardiovascular disease risk factor, potentially independent of moderate-to-vigorous physical activity (MVPA). However, little is known about environmental determinants of SED in Hispanic/Latino adults, a population disproportionately affected by metabolic conditions. PURPOSE: To investigate cross-sectional associations of micro- and macro-scale neighborhood environmental attributes with SED (volume and bouts) among Hispanic/Latino adults.METHODS: SED volume (standardized for a 16-hour day), mean SED bout length, and MVPA were objectively measured using accelerometry. Micro-scale environmental attributes (streetscape elements, aesthetics, crossing characteristics, street segments) were measured with a validated observation tool on a route starting at the participant's address. Macro-scale environmental attributes (walkability, greenness, transit, recreation) were objectively measured with GIS for 800-meter home neighborhood buffers. Complex samples linear regression models adjusted for individual characteristics, neighborhood socioeconomic deprivation, and MVPA tested the associations of each neighborhood attribute with SED. RESULTS: Individuals (n = 1776, 53% female; 45.7 ± 0.7 years) spent a weighted mean of 11.2 (SE = 0.1) hrs/day in SED time, with a weighted mean SED bout length of 9.1 (SE = 0.2) mins. Walkability was significantly and inversely associated with SED bout length (β: -0.14, 95% CI: -0.27, 0.00), but not SED volume (-1.76, 95% CI: -5.52, 2.00). No other macro- or micro-scale attributes were significantly associated with SED volume or bout length (see table). CONCLUSION: Among Hispanic/Latino adults, there was little support for cross-sectional associations between neighborhood attributes and SED (volume or bouts). Although neighborhood environment attributes have been consistently shown to relate to MVPA, they may be less important for SED.

Many ocular pathologies, including retinopathy of prematurity (ROP), diabetic retinopathy, and age-related macular degeneration, result in vision loss because of aberrant neoangiogenesis. A common feature of these conditions is the presence of hypoxic areas and overexpression of the proangiogenic vascular endothelial growth factor (VEGF). The prevailing current treatment, laser ablation of the retina, is destructive and only partially effective. Preventive and less destructive therapies are much more desirable. Here, we show that mice lacking c-Jun N-terminal kinase 1 (JNK1) exhibit reduced pathological angiogenesis and lower levels of retinal VEGF production in a murine model of ROP. We found that hypoxia induces JNK activation and regulates VEGF expression by enhancing the binding of phospho-c-Jun to the VEGF promoter. Intravitreal injection of a specific JNK inhibitor decreases retinal VEGF expression and reduces pathological retinal neovascularization without obvious side effects. These results strongly suggest that JNK1 plays a key role in retinal neoangiogenesis and that it represents a new pharmacological target for treatment of diseases where excessive neoangiogenesis is the underlying pathology.

Mitogen-activated protein kinase (MAPK) cascades are involved in inflammation and tissue destruction in rheumatoid arthritis (RA).In particular, c-Jun N-terminal kinase (JNK) is highly activated in RA fibroblast-like synoviocytes and synovium.However, defining the precise function of this kinase has been difficult because a selective JNK inhibitor has not been available.We now report the use of a novel selective JNK inhibitor and JNK knockout mice to determine the function of JNK in synoviocyte biology and inflammatory arthritis.The novel JNK inhibitor SP600125 (anthra[1,9-cd]pyrazol-6(2H)-one) completely blocked IL-1-induced accumulation of phospho-Jun and induction of c-Jun transcription in synoviocytes.Furthermore, AP-1 binding and collagenase mRNA accumulation were completely suppressed by SP600125.In contrast, complete inhibition of p38 had no effect, and ERK inhibition had only a modest effect.The essential role of JNK was confirmed in cultured synoviocytes from JNK1 knockout mice and JNK2 knockout mice, each of which had a partial defect in IL-1-induced AP-1 activation and collagenase-3 expression.Administration of SP600125 modestly decreased the rat paw swelling in rat adjuvant-induced arthritis.More striking was the near-complete inhibition of radiographic damage that was associated with decreased AP-1 activity and collagenase-3 gene expression.Therefore, JNK is a critical MAPK pathway for IL-1-induced collagenase gene expression in synoviocytes and in joint arthritis, indicating that JNK is an important therapeutic target for RA.

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