ABSTRACT
New therapeutics are a priority for preventing and eliminating Plasmodium vivax (Pv) malaria because of its easy transmissibility and dormant stages in the liver. Relapses due to the dormant liver stages are the major contributor to reoccurring Pv. Therefore, therapies that reduce the establishment of dormant parasites and blood-stage infection are important for controlling this geographically widespread parasite. Here, we isolated 12 human monoclonal antibodies (humAbs) from the plasma of a Pv-exposed individual that recognized Pv apical membrane antigen 1 (PvAMA1). PvAMA1 is important for both sporozoite invasion of hepatocytes and merozoite invasion of reticulocytes. We identified one humAb, 826827, that blocked invasion of human erythrocytes using a transgenic P. falciparum line expressing PvAMA1 (IC 50 = 3 µg/mL) and all Pv clinical isolates in vitro . This humAb also inhibited sporozoite invasion of a human hepatocyte cell line and primary human hepatocytes (IC 50 of 0.3 - 3.7 µg/mL). The crystal structure of recombinant PvAMA1 with the antigen-binding fragment of 826827 at 2.4 Å resolution shows that the humAb partially occupies the highly conserved hydrophobic groove in PvAMA1 that binds its known receptor, RON2. HumAb 826827 binds to PvAMA1 with higher affinity than RON2, accounting for its potency. To our knowledge, this is the first reported humAb specific to PvAMA1, and the PvAMA1 residues it binds to are highly conserved across different isolates, explaining its strain-transcendent properties.
ABSTRACT
Background: CXCL12/CXCR4 signaling is essential in cardiac development and repair, however, its contribution to aortic valve stenosis (AVS) remains unclear. In this study, we tested the role of endothelial CXCR4 on the development of AVS. Materials and methods: We generated CXCR4 endothelial cell-specific knockout mice (EC CXCR4 KO) by crossing CXCR4fl/fl mice with Tie2-Cre mice to study the role of endothelial cell CXCR4 in AVS. CXCR4fl/fl mice were used as controls. Echocardiography was used to assess the aortic valve and cardiac function. Heart samples containing the aortic valve were stained using Alizarin Red for detection of calcification. Masson's trichrome staining was used for the detection of fibrosis. The apex of the heart samples was stained with wheat germ agglutinin (WGA) to visualize ventricular hypertrophy. Results: Compared with the control group, the deletion of CXCR4 in endothelial cells led to significantly increased aortic valve peak velocity and aortic valve peak pressure gradient, with decreased aortic valve area and ejection fraction. EC CXCR4 KO mice also developed cardiac hypertrophy as evidenced by increased diastolic and systolic left ventricle posterior wall thickness (LVPW), cardiac myocyte size, and heart weight (HW) to body weight (BW) ratio. Our data also confirmed increased microcalcifications, interstitial fibrosis, and thickened valvular leaflets of the EC CXCR4 KO mice. Conclusion: The data collected throughout this study suggest the deletion of CXCR4 in endothelial cells is linked to the development of aortic valve stenosis and left ventricular hypertrophy. The statistically significant parameters measured indicate that endothelial cell CXCR4 plays an important role in aortic valve development and function. We have compiled compelling evidence that EC CXCR4 KO mice can be used as a novel model for AVS.
ABSTRACT
OBJECTIVES: While physical activity is important for health, many women do not meet recommended levels, particularly mothers. The purpose of this study was to assess whether physical activity levels differ by number of children at home in women aged 25-44 in the general US population. METHODS: This cross-sectional analysis used 2017 Behavioral Risk Factor Surveillance System data for females aged 25-44 (N = 6266) from California, Colorado, New York, Texas, and Utah. Ordered logistic regression analysis assessed the relationship between physical activity levels and number of children at home while controlling for state and demographic, socioeconomic, and health-related factors. RESULTS: About half of participants reported "inactive" or "insufficiently active" physical activity levels and about two-thirds reported having one or more children at home. The results of adjusted analysis indicated that physical activity level was significantly related to having one child (adjusted odds ratio = 0.75, 95% confidence interval = 0.63, 0.89), two children (adjusted odds ratio = 0.79; 95% confidence interval = 0.67, 0.93), and three or more children (adjusted odds ratio = 0.80, 95% confidence interval = 0.67, 0.94) at home. CONCLUSION: Overall, physical activity levels were significantly related to presence of children at home for women aged 25-44, but increasing number of children at home did not impact effect size. For women aged 25-44 in a primary care setting, a moderate prevalence of inactive or insufficiently active physical activity may be expected. Providers should address physical activity with all patients in this target population during well-visits, but particularly for women with children at home; educate patients about the health benefits of regular physical activity; and provide resources that will help them integrate physical activity into their daily lifestyles.
