Quantifying sources of variability in infancy research using the infant-directed-speech preference

Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure. (This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 798658.

Enpp1: a potential facilitator of breast cancer bone metastasis.

Bone is the most common site of breast cancer metastasis and once established, it is frequently incurable. Critical to our ability to prevent and treat bone metastasis is the identification of the key factors mediating its establishment and understanding their biological function. To address this issue we previously carried out an in vivo selection process to isolate murine mammary tumor sublines possessing an enhanced ability to colonize the bone. A comparison of gene expression between parental cells and sublines by genome-wide cDNA microarray analysis revealed several potential mediators of bone metastasis, including the pyrophosphate-generating ectoenzyme Enpp1. By qRT-PCR and Western analysis we found that expression of Enpp1 was elevated in human breast cancer cell lines known to produce bone metastasis in animal models compared to non-metastatic and normal mammary epithelial cell lines. Further, in clinical specimens, levels of Enpp1 were significantly elevated in human primary breast tumors relative to normal mammary epithelium, with highest levels observed in breast-bone metastasis as determined by qRT-PCR and immunohistochemical analysis. To examine the potential role of Enpp1 in the development of bone metastasis, Enpp1 expression was stably increased in the breast cancer cell line MDA-MB-231 and the ability to colonize the bone following intracardiac and direct intratibial injection of athymic nude mice was determined. By both routes of administration, increased expression of Enpp1 enhanced the ability of MDA-MB-231 cells to form tumors in the bone relative to cells expressing vector alone, as determined by digital radiography and histological analysis. Taken together, these data suggest a potential role for Enpp1 in the development of breast cancer bone metastasis

Enpp1: A Potential Facilitator of Breast Cancer Bone Metastasis

10.1371/journal.pone.0066752PLoS ONE87e6675

MIP-1δ activates NFATc1 and enhances osteoclastogenesis: involvement of both PLCγ2 and NFκB signaling.

Pathological bone resorption is a source of significant morbidity in diseases affecting the skeleton such as rheumatoid arthritis, periodontitis, and cancer metastasis to bone. Evidence indicates that elevated levels of inflammatory mediators such as IL-1, IL-6, and TNF-α play a role in this process by promoting the formation of bone-resorbing osteoclasts. Additionally, current studies have identified inflammatory chemokines of the macrophage inflammatory protein (MIP) family as potential mediators of pathological bone resorption, where both MIP-1α and -3α have been shown to enhance osteoclast (OCL) development. In this study we provide evidence that MIP-1δ, whose expression is associated with renal cell carcinoma bone metastasis and rheumatoid arthritis, enhances OCL formation in vitro via a direct effect on OCL precursors. Consistent with this ability, exposure of OCL precursors to MIP-1δ resulted in the activation of PLCγ2 and NF-κB, two signaling pathways known to regulate OCL differentiation. Moreover, MIP-1δ induced expression and nuclear translocation of NFATc1, a master regulator of osteoclastogenesis, which was dependent on activation of both the PLCγ2 and NFκB signaling pathways. Lastly, consistent with in vitro studies, in vivo administration of MIP-1δ significantly increased OCL number and resorption area as determined using a murine calvarial bone resorption model. Taken together, these data highlight the potential of MIP-1δ as a mediator of pathological bone resorption and provide insight into the molecular mechanism through which MIP-1δ enhances osteoclastogenesis

Expression of Enpp1 in human primary breast cancer and bone metastasis tissues.

<p>Enpp1 (<b>A</b>) mRNA and (<b>B–D</b>) protein expression in human normal mammary epithelium (N), primary breast tumor (T), and breast cancer bone metastasis (BBM) was determined by (A) qRT-PCR and (B–D) IHC analysis. (A) Data are representative of three independent experiments performed in triplicate (*<i>p</i><0.05 for T versus N). (B–D) Proteins were identified using DAB (brown). Sections were counterstained with hematoxylin and visualized by light microscopy (200X). N – Normal, T – Tumor.</p

Expression of Enpp1 in breast cancer cell lines.

<p>Enpp1 (<b>A, B</b>) mRNA and (<b>C</b>) protein expression was determined in (A) NT2.5 murine breast cancer cells and bone sublines, and (B, C) immortalized normal human mammary epithelial cell lines and human breast cancer cell lines by (A, B) qRT-PCR and (C) Western analysis. (A, B) Data are representative of three independent experiments performed in triplicate and expressed as the mean ± s.e.m (**p<0.01, ***p<0.001). (C) Protein expression was determined by Western analysis performed on equal amounts of protein from total cell lysates.</p

Effect of Enpp1 on the development of bone metastasis.

<p>MDA-MB-231 cells stably expressing Enpp1 or empty vector (EV) were injected into the (<b>A, B</b>) tibia (n = 9/group) and (<b>C, D</b>) left cardiac ventricle (n = 5/group) of athymic nude mice and digital radiographic imaging was performed at weekly intervals. (A, C) Osteolytic area and (B, D) tumor area were measured on radiographic images and histological sections, respectively (*<i>p</i><0.05, **<i>p<</i>0.01). Representative images are shown at 4 weeks following tumor cell administration. Black outlined areas on histological images indicate areas of tumor.</p