High CO2 Leads to Na,K-ATPase Endocytosis via c-Jun Amino-Terminal Kinase-Induced LMO7b Phosphorylation

The c-Jun amino-terminal kinase (JNK) plays a role in inflammation, proliferation, apoptosis, and cell adhesion and cell migration by phosphorylating paxillin and β-catenin. JNK phosphorylation downstream of AMP-activated protein kinase (AMPK) activation is required for high CO₂ (hypercapnia)-induced Na,K-ATPase endocytosis in alveolar epithelial cells. Here, we provide evidence that during hypercapnia, JNK promotes the phosphorylation of LMO7b, a scaffolding protein, in vitro and in intact cells. LMO7b phosphorylation was blocked by exposing the cells to the JNK inhibitor SP600125 and by infecting cells with dominant-negative JNK or AMPK adenovirus. The knockdown of the endogenous LMO7b or overexpression of mutated LMO7b with alanine substitutions of five potential JNK phosphorylation sites (LMO7b-5SA) or only Ser-1295 rescued both LMO7b phosphorylation and the hypercapnia-induced Na,K-ATPase endocytosis. Moreover, high CO₂ promoted the colocalization and interaction of LMO7b and the Na,K-ATPase α₁ subunit at the plasma membrane, which were prevented by SP600125 or by transfecting cells with LMO7b-5SA. Collectively, our data suggest that hypercapnia leads to JNK-induced LMO7b phosphorylation at Ser-1295, which facilitates the interaction of LMO7b with Na,K-ATPase at the plasma membrane promoting the endocytosis of Na,K-ATPase in alveolar epithelial cells.     

Tea consumption reduces ovarian cancer risk

Objective: To ascertain the relationship between tea drinking and the risk of ovarian cancer among southern Chinese women, a case–control study was conducted in southern China during 2006–2008. Methods: Five hundred incident patients with histologically confirmed epithelial carcinoma of the ovary and 500 controls (mean age 59 years) were recruited from four public hospitals in Guangzhou. Information on frequency, quantity and duration of tea drinking, amount of dried tea leaves brewed, together with habitual diet and lifestyle characteristics, was obtained face-to-face from participants using a validated and reliable questionnaire. Logistic regression analyses were performed to assess the association between tea consumption variables and the ovarian cancer risk. Results: The control subjects reported higher tea consumption levels and prevalence (78.8%) than the ovarian cancer patients (51.4%). Regular drinking of green tea, black tea and/or oolong tea was associated with a lower risk of ovarian cancer, the adjusted odds ratio being 0.29 (95% confidence interval 0.22–0.39) after accounting for confounding factors. When compared with non-drinkers, apparent inverse dose–response relationships were observed for years of drinking, number of cups and quantity of tea consumed, as well as amount of dried tea leaves brewed (p < 0.01). Conclusion: Regular tea consumption is associated with a reduced risk of ovarian cancer for southern Chinese women.     

Piloting Laboratory Quality System Management in Six Health Facilities in Nigeria

Background

Achieving accreditation in laboratories is a challenge in Nigeria like in most African countries. Nigeria adopted the World Health Organization Regional Office for Africa Stepwise Laboratory (Quality) Improvement Process Towards Accreditation (WHO/AFRO– SLIPTA) in 2010. We report on FHI360 effort and progress in piloting WHO-AFRO recognition and accreditation preparedness in six health facility laboratories in five different states of Nigeria.

Method

Laboratory assessments were conducted at baseline, follow up and exit using the WHO/AFRO– SLIPTA checklist. From the total percentage score obtained, the quality status of laboratories were classified using a zero to five star rating, based on the WHO/AFRO quality improvement stepwise approach. Major interventions include advocacy, capacity building, mentorship and quality improvement projects.

Results

At baseline audit, two of the laboratories attained 1- star while the remaining four were at 0- star. At follow up audit one lab was at 1- star, two at 3-star and three at 4-star. At exit audit, four labs were at 4- star, one at 3-star and one at 2-star rating. One laboratory dropped a ‘star’ at exit audit, while others consistently improved. The two weakest elements at baseline; internal audit (4%) and occurrence/incidence management (15%) improved significantly, with an exit score of 76% and 81% respectively. The elements facility and safety was the major strength across board throughout the audit exercise.

Conclusion

This effort resulted in measurable and positive impact on the laboratories. We recommend further improvement towards a formal international accreditation status and scale up of WHO/AFRO– SLIPTA implementation in Nigeria.     

An immunohistochemical study of adenohypophyseal cells containing follicle-stimulating hormone and luteinizing hormone during the phase of selective follicle-stimulating hormone release in postnatal female rats

Summary Serum concentration of follicle-stimulating hormone (FSH) in the juvenile female rat increases independently from that of luteinizing hormone (LH). The objective of this study was to determine whether this increase in serum FSH is accompanied by a proliferation of FSH-cells greater than the proliferation of LH-cells. Thus, we measured circulating FSH and LH in female rats on days 3, 10, 13, 17, and 20, calculated the percentages of adenohypophyseal cells that contained FSH or LH on days 3, 10, and 20, and determined whether cells containing only FSH existed on day 10. Serum FSH concentrations on days 10 and 13 were significantly greater than those on days 3, 17, or 20. No differences existed in serum LH concentrations. Cells containing FSH or LH were distributed throughout the entire adenohypophyses of 3, 10, and 20-day-old females. Clusters of these cells were observed in the ventral regions of adenohypophyses of 3-day-old females. The percentages of adenohypophyseal cells containing FSH increased significantly from 9% in 3-day-old rats to 17% in 10-day-old rats and then decreased to 14% in 20-day-old animals. At all ages the percentages of adenohypophyseal cells containing FSH were similar to the percentages of cells containing LH. At 10 days of age, all cells containing FSH also contained LH and all cells containing LH also contained FSH. These data suggest that the increase in serum FSH in the juvenile female rat is associated with an increase in the percentage of adenohypophyseal cells containing FSH and that at this time all cells containing FSH also contain LH.     

Role of calcitonin receptor-like receptor in colonic motility and inflammation

Calcitonin gene-related peptide (CGRP) mediates neurogenic inflammation and modulates intestinal motility. The CGRP receptor is a heterodimer of calcitonin receptor-like receptor (CLR) and receptor-associated modifying protein 1. We used RNA interference to elucidate the specific role of CLR in colonic motility and inflammation. Intramural injection of double-stranded RNA (dsRNA) against CLR (dsCLR) into the colonic wall at two sites caused the spatial and temporal downregulation of CLR in the colon within 1 day of dsRNA injection. Knockdown of CLR persisted for 7-9 days, and the effect of knockdown spread to approximately 2 cm proximal and distal to the injection sites, whereas control dsRNA injection did not affect CLR expression. Measurement of isometric contractions of isolated colonic muscle segments revealed that in control dsRNA-injected rats, CGRP abrogated contractions entirely and decreased resting muscular tone, whereas in dsCLR-injected rats, CGRP decreased muscle tone but slow-wave contractions of varying amplitude persisted. In trinitrobenzene sulfonic acid-induced colitis, rats with knockdown of CLR displayed a significantly greater degree of edema and necrosis than saline- or control dsRNA-injected rats. Levels of the proinflammatory cytokines TNF-alpha and IL-6 were markedly upregulated by trinitrobenzene sulfonic acid treatment. TNF-alpha mRNA levels were further increased in CLR knockdown rats, whereas levels of IL-6 were unaltered. Thus this study demonstrates that CLR is a functional receptor for CGRP.     

Genetic analysis reveals promiscuity among female cheetahs

Cheetahs (Acinonyx jubatus) have a combination of ranging patterns and social system that is unique in mammals, whereby male coalitions occupy small territories less than 10% of the home range of solitary females. This study uses non-invasive genetic sampling of a long-term study population of cheetah in the Serengeti National Park in Tanzania to infer the mating system. Individual cheetah genotypes at up to 13 microsatellite loci were obtained from 171 faecal samples. A statistical method was adapted to partition the cubs within each litter (n=47) into full-sibling clusters and to infer the father of each cluster using these loci. Our data showed a high rate of multiple paternity in the population; 43% of litters with more than one cub were fathered by more than one male. The results also demonstrated that female fidelity was low, and provided some evidence that females chose to mate with unrelated males within an oestrus cycle. The low rate of paternity assignments indicated that males living outside the study area contributed substantially to the reproduction of the cheetah population.     

The effect of thyroid hormones on the membrane adenylate cyclase activity in sickle red blood cells in vitro

A comparative study of thyroid hormone responsive membrane adenylate cyclase activity has been carried out on normal (Hb-AA) and sickle cell (Hb-SS) subjects. Thyroid hormones (T3 and T4) and selected analogues (TRIAC and DLT) enhanced adenylate cyclase activity in Hb-AA membranes. The interaction of Hb-SS membranes with the hormones and analogues was not significant except for T3 which moderately stimulated Hb-SS membrane adenylate cyclase. We suggest that circulating irreversibly sickled cells, in view of their membrane phospholipid defect, probably contribute to the low response of membrane adenylate cyclase to effector stimulation.     

The cytosol as site of phosphorylation of the cyclic AMP-dependent protein kinase in adrenal steroidogenesis

The mitochondria, the microsomes and the cystosol have been described as possible sites of cAMP-dependent phosphorylation. However, there has been no direct demonstration of a cAMP-dependent kinase associated with the activation of the side-chain cleavage of cholesterol. We have investigated the site of action of the cAMP-dependent kinase using a sensitive cell-free assay. Cytosol derived from cells stimulated with ACTH or cAMP was capable of increasing progesterone synthesis in isolated mitochondria when combined with the microsomal fraction. Cytosol derived from cyclase or kinase of negative mutant cells did not. Cyclic AMP and cAMP-dependent protein kinase stimulated in vitro a cytosol derived from unstimulated adrenal cells. This cytosol was capable of stimulating progesterone synthesis in isolated mitochondria. Inhibitor of cAMP-dependent protein kinase abolished the effect of the cAMP. ACTH stimulation of cytosol factors is a rapid process observable with a half maximal stimulation at about 3 pM ACTH. The effect was also abolished by inhibitor of arachidonic acid release. The function of cytosolic phosphorylation is still unclear. The effect of inhibitors of arachidonic acid release, and the necessity for the microsomal compartment in order to stimulate mitochondrial steroidogenesis, suggest that the factor in the cytosol may play a role in arachidonic acid release.