Fermitin family homolog-2 (FERMT2) is highly expressed in human placental villi and modulates trophoblast invasion.

BACKGROUND: Integrins are transmembrane receptors that mediate cell-extracellular matrix (ECM) and cell-cell adhesion and trophoblast cells undergo changes in integrin expression as they differentiate. However, the mechanism(s) of integrin activation leading to integrin-mediated signaling in trophoblast cell differentiation is unknown. The Fermitin family proteins are integrin activators that help mediate integrin-mediated signaling, but have never been studied in detail within the human placenta. Thus, we examined the spatiotemporal pattern of expression of Fermitin family homolog-2 (FERMT2) in human chorionic villi throughout gestation and its role in trophoblast-substrate adhesion and invasion. METHODS: Placental villous tissue was obtained from patients undergoing elective terminations by dilatation and curettage at weeks 8-12 (n = 10), weeks 13-14 (n = 8), as well as from term deliveries at weeks 37-40 (n = 6). Tissues were fixed, processed and sections utilized for immunofluorescence analysis of FERMT2 expression during gestation. Additionally, HTR8-SVneo human trophoblast cells were transfected by electroporation with FERMT2-specific siRNAs or non-targeting siRNAs (control) and used in cell-substrate adhesion as well as invasion assays. RESULTS: FERMT2 was more commonly expressed in the basal domain of villous cytotrophoblast cells and prominently localized around the periphery of individual extravillous trophoblast cells. siRNA-mediated knockdown of FERMT2 in HTR8-SVneo cells resulted in significantly decreased trophoblast-substrate attachment (p < 0.05) as well as significantly decreased trophoblast invasion (p < 0.05) relative to control cells. CONCLUSIONS: The detection of FERMT2 throughout extravillous trophoblast columns and the results of invasion assays demonstrated that this protein is likely an important regulator of integrin activation in extravillous cells to modulate migration and invasion.

The Jackson Heart KIDS Pilot Study: Theory-Informed Recruitment in an African American Population.

Recruitment for large cohort studies is typically challenging, particularly when the pool of potential participants is limited to the descendants of individuals enrolled in a larger, longitudinal "parent" study. The increasing complexity of family structures and dynamics can present challenges for recruitment in offspring. Few best practices exist to guide effective and efficient empirical approaches to participant recruitment. Social and behavioral theories can provide insight into social and cultural contexts influencing individual decision-making and facilitate the development strategies for effective diffusion and marketing of an offspring cohort study. The purpose of this study was to describe the theory-informed recruitment approaches employed by the Jackson Heart KIDS Pilot Study (JHKS), a prospective offspring feasibility study of 200 African American children and grandchildren of the Jackson Heart Study (JHS)-the largest prospective cohort study examining cardiovascular disease among African American adults. Participant recruitment in the JHKS was founded on concepts from three theoretical perspectives-the Diffusion of Innovation Theory, Strength of Weak Ties, and Marketing Theory. Tailored recruitment strategies grounded in participatory strategies allowed us to exceed enrollment goals for JHKS Pilot Study and develop a framework for a statewide study of African American adolescents.

Extracellular acidosis activates ASIC-like channels in freshly isolated cerebral artery smooth muscle cells.

Recent studies suggest that certain acid-sensing ion channels (ASIC) are expressed in vascular smooth muscle cells (VSMCs) and are required for VSMC functions. However, electrophysiological evidence of ASIC channels in VSMCs is lacking. The purpose of this study was to test the hypothesis that isolated cerebral artery VSMCs express ASIC-like channels. To address this hypothesis, we used RT-PCR, Western blotting, immunolabeling, and conventional whole cell patch-clamp technique. We found extracellular H(+)-induced inward currents in 46% of cells tested (n = 58 of 126 VSMCs, pH 6.5-5.0). The percentage of responsive cells and the current amplitude increased as the external H(+) concentration increased (pH(6.0), n = 28/65 VSMCs responsive, mean current density = 8.1 +/- 1.2 pA/pF). Extracellular acidosis (pH(6.0)) shifted the whole cell reversal potential toward the Nernst potential of Na(+) (n = 6) and substitution of extracellular Na(+) by N-methyl-d-glucamine abolished the inward current (n = 6), indicating that Na(+) is a major charge carrier. The broad-spectrum ASIC blocker amiloride (20 microM) inhibited proton-induced currents to 16.5 +/- 8.7% of control (n = 6, pH(6.0)). Psalmotoxin 1 (PcTx1), an ASIC1a inhibitor and ASIC1b activator, had mixed effects: PcTx1 either 1) abolished H(+)-induced currents (11% of VSMCs, 5/45), 2) enhanced or promoted activation of H(+)-induced currents (76%, 34/45), or 3) failed to promote H(+) activation in nonresponsive VSMCs (13%, 6/45). These findings suggest that freshly dissociated cerebral artery VSMCs express ASIC-like channels, which are predominantly formed by ASIC1b.

Impaired pressure-induced constriction in mouse middle cerebral arteries of ASIC2 knockout mice.

Recent studies from our laboratory demonstrated the importance of mechanosensitive epithelial Na(+) channel (ENaC) proteins in pressure-induced constriction in renal and cerebral arteries. ENaC proteins are closely related to acid-sensing ion channel 2 (ASIC2), a protein known to be required for normal mechanotransduction in certain sensory neurons. However, the role of the ASIC2 protein in pressure-induced constriction has never been addressed. The goal of the current study was to investigate the role of ASIC2 proteins in pressure-induced, or myogenic, constriction in the mouse middle cerebral arteries (MCAs) from ASIC2 wild-type (+/+), heterozygous (+/-), and null (-/-) mice. Constrictor responses to KCl (20-80 mM) and phenylephrine (10(-7)-10(-4) M) were not different among groups. However, vasoconstrictor responses to increases in intraluminal pressure (15-90 mmHg) were impaired in MCAs from ASIC2(-/-) and (+/-) mice. At 60 and 90 mmHg, MCAs from ASIC2(+/+) mice generated 13.7 +/- 2.1% and 15.8 +/- 2.0% tone and ASIC2(-/-) mice generated 7.4 +/- 2.8% and 12.5 +/- 2.4% tone, respectively. Surprisingly, MCAs from ASIC2(+/-) mice generated 1.2 +/- 2.2% and 3.9 +/- 1.8% tone at 60 and 90 mmHg. The reason underlying the total loss of myogenic tone in the ASIC2(+/-) is not clear, although the loss of mechanosensitive beta- and gamma-ENaC proteins may be a contributing factor. These results demonstrate that normal ASIC2 expression is required for normal pressure-induced constriction in the MCA. Furthermore, ASIC2 may be involved in establishing the basal level of myogenic tone.

ASIC proteins regulate smooth muscle cell migration.

The purpose of the present study was to investigate Acid Sensing Ion Channel (ASIC) protein expression and importance in cellular migration. We recently demonstrated that Epithelial Na(+)Channel (ENaC) proteins are required for vascular smooth muscle cell (VSMC) migration; however, the role of the closely related ASIC proteins has not been addressed. We used RT-PCR and immunolabeling to determine expression of ASIC1, ASIC2, ASIC3 and ASIC4 in A10 cells. We used small interference RNA to silence individual ASIC expression and determine the importance of ASIC proteins in wound healing and chemotaxis (PDGF-bb)-initiated migration. We found ASIC1, ASIC2, and ASIC3, but not ASIC4, expression in A10 cells. ASIC1, ASIC2, and ASIC3 siRNA molecules significantly suppressed expression of their respective proteins compared to non-targeting siRNA (RISC) transfected controls by 63%, 44%, and 55%, respectively. Wound healing was inhibited by 10, 20, and 26% compared to RISC controls following suppression of ASIC1, ASIC2, and ASIC3, respectively. Chemotactic migration was inhibited by 30% and 45%, respectively, following suppression of ASIC1 and ASIC3. ASIC2 suppression produced a small, but significant, increase in chemotactic migration (4%). Our data indicate that ASIC expression is required for normal migration and may suggest a novel role for ASIC proteins in cellular migration.

Hemodialysis adequacy and quality of life: how do they relate?

There is clear evidence of a link between dialysis adequacy (as measured by urea kinetic modelling or urea reduction ratio) and such important clinical outcomes as morbidity and mortality. Evidence regarding the relationship between dialysis adequacy and quality of life outcomes is less clear. This paper reports the results of a study designed to answer the following research question: What is the impact of changing dialysis adequacy on functional status and well-being in a sample of new hemodialysis patients? The study employed a convenience sampling technique enrolling all willing new patients who started hemodialysis for a four-year period. The final sample size was 69. The adequacy of each new patient's dialysis prescription was determined by calculating Kt/V at one and three months following the start of dialysis. Changes to dialysis prescriptions were made, as necessary, to achieve a minimum Kt/V of 1.2. Each subject's quality of life was measured at the same time intervals, using two instruments. The first instrument, the SF-36, is a generic 36-item instrument designed to measure a range of functioning and well-being. The second instrument, the Kidney Disease Questionnaire (KDQ), is a disease-specific quality of life instrument designed for use with chronic hemodialysis patients. The results of this study demonstrated a significant positive relationship (p < .05) between Kt/V and four of five variables in the KDQ, and two of eight variables in the SF-36. These variables were predominantly in the social/emotional well-being domain.