Expansive growth of two glioblastoma stem-like cell lines is mediated by bFGF and not by EGF

Background

Patient-derived glioblastoma (GBM) stem-like cells (GSCs) represent a valuable model for basic and therapeutic research. GSCs are usually propagated in serum-free Neural Basal medium supplemented with bFGF and EGF. Yet, the exact influence of these growth factors on GSCs is still unclear. Recently it was suggested that GBM stem-like cells with amplified EGFR should be cultured in stem cell medium without EGF, as the presence of EGF induced rapid loss of EGFR amplification. However, patient biopsies are usually taken into culture before their genomic profiles are defined. Thus, an important question remains whether GBM cells without EGFR amplification also can be cultured in stem cell medium without EGF.

Meterials and methods

To address this question, we used two heterogeneous glioblastoma GSC lines (NCH421k and NCH644) that lack EGFR amplification.

Results

Although both cell lines showed very low EGFR expression under standard growth conditions, bFGF stimulation induced higher expression of EGFR in NCH644. In both cell lines, expression of the stem cell markers nestin and CD133 was higher upon stimulation with bFGF compared to EGF. Importantly, bFGF stimulated the growth of both cell lines, whereas EGF had no effect. We verified that the growth stimulation by bFGF was either mediated by proliferation (NCH421k) or resistance to apoptosis (NCH644).

Conclusions

We demonstrate that GSC cultures without EGFR amplification can be maintained and expanded with bFGF, while the addition of EGF has no significant effect and therefore can be omitted.     

Silver nanoparticles induce neurotoxicity in a human embryonic stem cell-derived neuron and astrocyte network

Silver nanoparticles (AgNPs) are among the most extensively used nanoparticles and are found in a variety of products. This ubiquity leads to inevitable exposure to these particles in everyday life. However, the effects of AgNPs on neuron and astrocyte networks are still largely unknown. In this study, we used neurons and astrocytes derived from human embryonic stem cells as a cellular model to study the neurotoxicity that is induced by citrate-coated AgNPs (AgSCs). Immunostaining with the astrocyte and neuron markers, glial fibrillary acidic protein and microtubule-associated protein-2 (MAP2), respectively, showed that exposure to AgSCs at the concentration of 0.1?µg/mL increased the astrocyte/neuron ratio. In contrast, a higher concentration of AgSCs (5.0?µg/ml) significantly changed the morphology of astrocytes. These results suggest that astrocytes are sensitive to AgSC exposure and that low concentrations of AgSCs promote astrogenesis. Furthermore, our results showed that AgSCs reduced neurite outgrowth, decreased the expression of postsynaptic density protein 95 and synaptophysin, and induced neurodegeneration in a concentration-dependent manner. Our findings additionally suggest that the expression and phosphorylation status of MAP2 isoforms, as modulated by the activation of the Akt/glycogen synthase kinase-3/caspase-3 signaling pathway, may play an important role in AgSC-mediated neurotoxicity. We also found that AgNO₃ exposure only slightly reduced neurite outgrowth and had little effect on MAP2 expression, suggesting that AgSCs and AgNO₃ have different neuronal toxicity mechanisms. In addition, most of these effects were reduced when the cell culture was co-treated with AgSCs and the antioxidant ascorbic acid, which implies that oxidative stress is the major cause of AgSC-mediated astrocytic/neuronal toxicity and that antioxidants may have a neuroprotective effect.     

Community-Based Accompaniment and the Impact of Distance for HIV Patients Newly Initiated on Antiretroviral Therapy: Early Outcomes and Clinic Visit Adherence in Rural Rwanda

Community-based accompaniment (CBA) has been associated with improved antiretroviral therapy (ART) patient outcomes in Rwanda. In contrast, distance has generally been associated with poor outcomes. However, impact of distance on outcomes under the CBA model is unknown. This retrospective cohort study included 537 adults initiated on ART in 2012 in two rural districts in Rwanda. The primary outcomes at 6 months after ART initiation included overall program status, missed a visit and missed three consecutive visits. The associations between cost surface distance (straight-line distance adjusted for surface features) and outcomes were assessed using logistic regression, controlling for potential confounders. Died/lost-to-follow-up and missed three consecutive visits were not associated with distance. Patients within 0–1 km cost surface distance were significantly more likely to miss a visit, potentially due to stigma of attending clinic within one’s community. These results suggest that CBA may mediate the impact of long distances on outcomes.     

Epidemiology of rotavirus diarrhoea in Albania

The aim of the study was to estimate the prevalence of rotavirus disease in children <5 years old in Tirana, Albania, and to monitor and characterize the rotavirus genotypes. Rotavirus was detected in 21 % of samples, more frequently in children under 2 years of age, which accounted for 80.8 % of all positive cases. Among all rotavirus-positive samples collected, G4P[8] was the most prevalent genotype (38 %), followed by G1P[8] (36.6 %). The use of safe and effective rotavirus vaccines for the prevention of severe diarrhoea and the reduction of treatment costs will be of great importance for Albania.     

Public-private options for expanding access to human resources for HIV/AIDS in Botswana

In responding to the goal of rapidly increasing access to antiretroviral treatment (ART), the government of Botswana undertook a major review of its health systems options to increase access to human resources, one of the major bottlenecks preventing people from receiving treatment. In mid-2004, a team of government and World Health Organization (WHO) staff reviewed the situation and identified a number of public sector scale up options. The team also reviewed the capacity of private practitioners to participate in the provision of ART. Subsequently, the government created a mechanism to include private practitioners in rolling out ART. At the end of 2006, more than 4500 patients had been transferred to the private sector for routine follow up. It is estimated that the cooperation reduced the immediate need for recruiting up to 40 medically qualified staff into the public sector over the coming years, depending on the development of the national standard for the number and duration of patient visits to a doctor per year. Thus welcome relief was brought, while at the same time not exercising a pull factor on human resources for health in the sub-Saharan region.     

Aggressive behaviors in adult SF-1 knockout mice that are not exposed to gonadal steroids during development

Sex hormones are a major factor responsible for the development of sex differences. Steroidogenic factor 1 (SF-1) is a key regulator of gonadal and adrenal development, and SF-1 knockout mice (SF-1 KO) are born without gonads and adrenal glands. Consequently, these mice are not exposed to gonadal sex steroids. SF-1 KO pups die shortly after birth due to adrenal deficiency. In the present study, SF-1 KO mice were rescued by neonatal corticosteroid injections followed by adrenal transplantations on day 7-8 postnatally. Control mice received corticosteroid injections and were gonadectomized prior to puberty. Mice were observed interacting with ovariectomized hormone primed females and gonad-intact males. In the absence of sex steroid replacement, adult SF-1 KO mice were significantly more aggressive than control mice in tests with stimulus females. After testosterone treatment, control males displayed significantly more aggression towards male intruders than control female mice, or male and female SF-1 KO mice, suggesting a developmental role of gonadal hormones in the expression of aggressive behavior and affirming SF-1 KO mice as a behavioral model to investigate affects of fetal gonad deficiency.     

Overexpression of survival motor neuron improves neuromuscular function and motor neuron survival in mutant SOD1 mice

Spinal muscular atrophy results from diminished levels of survival motor neuron (SMN) protein in spinal motor neurons. Low levels of SMN also occur in models of amyotrophic lateral sclerosis (ALS) caused by mutant superoxide dismutase 1 (SOD1) and genetic reduction of SMN levels exacerbates the phenotype of transgenic SOD1^G93A mice. Here, we demonstrate that SMN protein is significantly reduced in the spinal cords of patients with sporadic ALS. To test the potential of SMN as a modifier of ALS, we overexpressed SMN in 2 different strains of SOD1^G93A mice. Neuronal overexpression of SMN significantly preserved locomotor function, rescued motor neurons, and attenuated astrogliosis in spinal cords of SOD1^G93A mice. Despite this, survival was not prolonged, most likely resulting from SMN mislocalization and depletion of gems in motor neurons of symptomatic mice. Our results reveal that SMN upregulation slows locomotor deficit onset and motor neuron loss in this mouse model of ALS. However, disruption of SMN nuclear complexes by high levels of mutant SOD1, even in the presence of SMN overexpression, might limit its survival promoting effects in this specific mouse model. Studies in emerging mouse models of ALS are therefore warranted to further explore the potential of SMN as a modifier of ALS.