Mendelian Randomization Analysis of the Relationship Between Native American Ancestry and Gallbladder Cancer Risk

Background A strong association between the proportion of Native American ancestry and the risk of gallbladder cancer (GBC) has been reported in observational studies. Chileans show the highest incidence of GBC worldwide, and the Mapuche are the largest Native American people in Chile. We set out to investigate the causal association between Native American Mapuche ancestry and GBC risk, and the possible mediating effects of gallstone disease and body mass index (BMI) on this association. Methods Markers of Mapuche ancestry were selected based on the informativeness for assignment measure and then used as instrumental variables in two-sample mendelian randomization (MR) analyses and complementary sensitivity analyses. Result We found evidence of a causal effect of Mapuche ancestry on GBC risk (inverse variance-weighted (IVW) risk increase of 0.8% for every 1% increase in Mapuche ancestry proportion, 95% CI 0.4% to 1.2%, p = 6.6×10-5). Mapuche ancestry was also causally linked to gallstone disease (IVW risk increase of 3.6% per 1% increase in Mapuche proportion, 95% CI 3.1% to 4.0%, p = 1.0×10-59), suggesting a mediating effect of gallstones in the relationship between Mapuche ancestry and GBC. In contrast, the proportion of Mapuche ancestry showed a negative causal effect on BMI (IVW estimate -0.006 kg/m2 per 1% increase in Mapuche proportion, 95% CI -0.009 to -0.003, p = 4.4×10-5). Conclusions The results presented here may have significant implications for GBC prevention and are important for future admixture mapping studies. Given that the association between Mapuche ancestry and GBC risk previously noted in observational studies appears to be causal, primary and secondary prevention strategies that take into account the individual proportion of Mapuche ancestry could be particularly efficient

Región endémica y regímenes de infección con el virus del síndrome de la mancha blanca (wssv) en las granjas camaronícolas del noroeste de México

El cultivo de camarón, con un valor aproximado de 711 millones de dólares anuales, es una de las actividades primarias más importantes en México. Sin embargo, ha tenido que enfrentar diversos problemas que han limitado su desarrollo, dentro de los cuales la mortalidad causada por el virus del síndrome de la mancha blanca (WSSV) es el más importante. Para contar con elementos científicos enfocados a acciones de manejo sanitario preventivo, es preciso conocer, entre otros elementos, aspectos de la epidemiología de la enfermedad de la mancha blanca (WSD). Por esta razón el presente trabajo se enfocó a delimitar la región endémica de la WSD, sus regímenes temporales de infección y la discusión sobre los posibles factores de riesgo que pueden estar relacionados con sus brotes en las granjas camaronícolas del noroeste de México. Se utilizó información de las bases de datos de los Comités Estatales de Sanidad Acuícola de Baja California Sur, Sonora, Sinaloa y Nayarit; así como del Programa Integral de Sanidad Acuícola en Camarón (PISA 2007-2008) y de la Alianza Estratégica y Red de Innovación de la Industria Acuícola (AERI-2008). El análisis de la información mostró, para los ciclos de producción de camarón 2007-2008, una región endémica con presencia del virus WSSV, ubicada entre la región de Tuxpan, Nayarit al sur y de Agiabampo, Sonora, al norte. Los brotes de primavera de la WSD en las granjas acuícolas tuvieron un desplazamiento espacio-temporal, indicando tres regímenes de infección: (1) marzo-abril en la región sur del área de cultivo (Juntas Locales de Sanidad Acuícola [JLSA] de Mazatlán, El Rosario, Escuinapa, Tecuala y Tuxpan); (2) abril-mayo al centro (JLSA de Navolato Norte y Sur y El dorado); (3) mayo-junio en la parte norte (JLSA de Agiabampo-Sonora, Ahome, Guasave Norte y Sur). Los registros de la WSD fueron consistentes entre el 2007 y el 2008, con ligeras variaciones en algunas JLSA respecto al inicio o presencia de los brotes en primavera. Se muestra la asociación de los regímenes de infección a lo largo de la región endémica con la ubicación de las cuencas oceanográficas de Mazatlán, Pescadero y Farallón, en función del incremento diferencial de la temperatura dentro de ellas, la cual puede ser un factor condicionante para la presencia de brotes de la WSD

Purinergic Signaling Pathway in Human Olfactory Neuronal Precursor Cells

Extracellular ATP and trophic factors released by exocytosis modulate in vivo proliferation, migration, and differentiation in multipotent stem cells (MpSC); however, the purinoceptors mediating this signaling remain uncharacterized in stem cells derived from the human olfactory epithelium (hOE). Our aim was to determine the purinergic pathway in isolated human olfactory neuronal precursor cells (hONPC) that exhibit MpSC features. Cloning by limiting dilution from a hOE heterogeneous primary culture was performed to obtain a culture predominantly constituted by hONPC. Effectiveness of cloning to isolate MpSC-like precursors was corroborated through immunodetection of specific protein markers and by functional criteria such as self-renewal, proliferation capability, and excitability of differentiated progeny. P2 receptor expression in hONPC was determined by Western blot, and the role of these purinoceptors in the ATP-induced exocytosis and changes in cytosolic Ca2+ ([Ca2+]i) were evaluated using the fluorescent indicators FM1-43 and Fura-2 AM, respectively. The clonal culture was enriched with SOX2 and OCT3/4 transcription factors; additionally, the proportion of nestin-immunopositive cells, the proliferation capability, and functionality of differentiated progeny remained unaltered through the long-term clonal culture. hONPC expressed P2X receptor subtypes 1, 3-5, and 7, as well as P2Y2, 4, 6, and 11; ATP induced both exocytosis and a transient [Ca2+]i increase predominantly by activation of metabotropic P2Y receptors. Results demonstrated for the first time that ex vivo-expressed functional P2 receptors in MpSC-like hONPC regulate exocytosis and Ca2+ signaling. This purinergic-triggered release of biochemical messengers to the extracellular milieu might be involved in the paracrine signaling among hOE cells

Detection of white spot syndrome virus in filtered shrimp-farm water fractions and experimental evaluation of its infectivity in Penaeus (Litopenaeus) vannamei

White spot syndrome virus (WSSV) may spread through water to neighbor ponds or farms. Routine water exchange and wastewater released during white spot disease (WSD)-emergency harvests may preserve WSSV in shrimp farming areas. To test this hypothesis, on-site experiments were performed in a WSSV-affected farm in Guasave, Sinaloa, Mexico. Plankton and shrimp hemolymph were collected from 12 ponds during a WSD outbreak. PCR analyses showed that 72% of the hemolymph pools (26 out of 36) were WSSV-positive. In contrast, only 14% (4 of 28) plankton samples (filtered through 10 and 0.45 µm) from three ponds (2, 7 and 10) were WSSV-positive. Plankton from pond 9 was WSSV-negative, but 14 days later, shrimp began to die. At this point, a differential filtration experiment was performed in pond 9. WSSV-positive samples were only found in three fractions [particulate fraction (PF) 1 µm and liquid fractions (LF) 0.65 µm) became WSSV-positive. Results indicate that water fractions between 100 and 0.65 µm induced WSSV infection to shrimp. Results showed that pond water and/or particulate fractions are vehicles for WSSV dispersion via virus suspended in water, attached to microalgae, or carried by zooplankton

Maximum diastolic potential of human induced pluripotent stem cell-derived cardiomyocytes depends critically on I(Kr).

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) hold promise for therapeutic applications. To serve these functions, the hiPSC-CM must recapitulate the electrophysiologic properties of native adult cardiomyocytes. This study examines the electrophysiologic characteristics of hiPSC-CM between 11 and 121 days of maturity. Embryoid bodies (EBs) were generated from hiPS cell line reprogrammed with Oct4, Nanog, Lin28 and Sox2. Sharp microelectrodes were used to record action potentials (AP) from spontaneously beating clusters (BC) micro-dissected from the EBs (n = 103; 37°C) and to examine the response to 5 µM E-4031 (n = 21) or BaCl(2) (n = 22). Patch-clamp techniques were used to record I(Kr) and I(K1) from cells enzymatically dissociated from BC (n = 49; 36°C). Spontaneous cycle length (CL) and AP characteristics varied widely among the 103 preparations. E-4031 (5 µM; n = 21) increased Bazett-corrected AP duration from 291.8±81.2 to 426.4±120.2 msec (p<0.001) and generated early afterdepolarizations in 8/21 preparations. In 13/21 BC, E-4031 rapidly depolarized the clusters leading to inexcitability. BaCl(2), at concentrations that selectively block I(K1) (50-100 µM), failed to depolarize the majority of clusters (13/22). Patch-clamp experiments revealed very low or negligible I(K1) in 53% (20/38) of the cells studied, but presence of I(Kr) in all (11/11). Consistent with the electrophysiological data, RT-PCR and immunohistochemistry studies showed relatively poor mRNA and protein expression of I(K1) in the majority of cells, but robust expression of I(Kr.) In contrast to recently reported studies, our data point to major deficiencies of hiPSC-CM, with remarkable diversity of electrophysiologic phenotypes as well as pharmacologic responsiveness among beating clusters and cells up to 121 days post-differentiation (dpd). The vast majority have a maximum diastolic potential that depends critically on I(Kr) due to the absence of I(K1). Thus, efforts should be directed at producing more specialized and mature hiPSC-CM for future therapeutic applications

Infection of WSSV-negative Shrimp, Litopenaeus vannamei, Cultivated under Fluctuating Temperature Conditions

To test whether effluents released from white spot syndrome virus (WSSV)-infected farm ponds are a pathway for spreading WSSV, WSSV-negative Pacific whiteleg shrimp, Litopenaeus vannamei, were exposed to WSSV-containing water under conditions of fluctuating water temperatures. White spot disease outbreaks occurred at the shrimp ponds before and during the experiment. Two cages were placed inside each test pond, and one was placed at the outlet canal. Each cage was stocked with 30 shrimp. Hemolymph from stocked shrimp was collected at intervals of 24, 48, 72, 120, 168, and 360 h after exposure and analyzed for presence of WSSV DNA by nested polymerase chain reaction. At diurnal variation of water temperature from 28.0 to 33.4 C, WSSV was detected as early as 120 h (ca. 11% of shrimp hemolymph pools) and 168 h (ca. 18% of shrimp hemolymph pools). WSSV was detected by 360 h (ca. 33% of shrimp hemolymph pools) in all cages, when water temperature varied from 24.9 to 28.5 C during a 48-h period. Cumulative mortality in cages inside ponds was ≤50.0 and 86.7% at the outlet canal. These data show that grow-out operations during the summer–autumn transition are at risk of WSSV outbreaks. The experiment demonstrated that WSSV can be spread by shrimp farm water drainage

Expression of H v 1 proton channels in myeloid-derived suppressor cells (MDSC) and its potential role in T cell regulation

Myeloid-derived suppressor cells (MDSC) are a heterogeneous cell population with high immunosuppressive activity that proliferates in infections, inflammation, and tumor microenvironments. In tumors, MDSC exert immunosuppression mainly by producing reactive oxygen species (ROS), a process triggered by the NADPH oxidase 2 (NOX2) activity. NOX2 is functionally coupled with the Hv1 proton channel in certain immune cells to support sustained free-radical production. However, a functional expression of the Hv1 channel in MDSC has not yet been reported. Here, we demonstrate that mouse MDSC express functional Hv1 proton channel by immunofluorescence microscopy, flow cytometry, and Western blot, besides performing a biophysical characterization of its macroscopic currents via patch-clamp technique. Our results show that the immunosuppression by MDSC is conditional to their ability to decrease the proton concentration elevated by the NOX2 activity, rendering Hv1 a potential drug target for cancer treatment

Concentration-dependence of the effect of BaCl₂ on AP amplitude and V_max.

<p>Concentration-dependence of the effect of BaCl₂ to reduce AP amplitude, V_max and MDP in two population of beating clusters (BC). 100 µM BaCl₂ induced no changes in MDP in 13 out of 22 BC suggesting a small contribution or lack of I_K1 (<b>A, </b><b>C and E</b>), but led to membrane depolarization in 9 out of 22 BC (<b>B, D and F</b>). At concentrations at which BaCl₂ also blocks I_Kr (500 µM), AP amplitude and V_max decreased in both groups of BC. a: p<0.05 vs. Control; c: p<0.001 vs. Control.</p

Summary data of the effect of E-4031.

<p>Electrophysiologic parameters measured under control conditions and following 5 µM E-4031 from beating clusters in which this intervention led to EADs (A, n = 8 [29 to 116 days old]) and from those in which it did not (B; n = 13 [25 to 118 days old]). Values are means ± SD. a: p<0.05 vs. Control; b: p<0.001 vs. B; c: p<0.01 vs. Control; d: p<0.005 vs. Control; e: p<0.05 vs. B; f: p<0.001 vs. Control; g: p<0.01 vs. B.</p