Serotonin-induced hyperactivity in SSRI-resistant major depressive disorder patient-derived neurons.

Selective serotonin reuptake inhibitors (SSRIs) are the most prescribed antidepressants. They regulate serotonergic neurotransmission, but it remains unclear how altered serotonergic neurotransmission may contribute to the SSRI resistance observed in approximately 30% of major depressive disorder (MDD) patients. Patient stratification based on pharmacological responsiveness and the use of patient-derived neurons may make possible the discovery of disease-relevant neural phenotypes. In our study from a large cohort of well-characterized MDD patients, we have generated induced pluripotent stem cells (iPSCs) from SSRI-remitters and SSRI-nonremitters. We studied serotonergic neurotransmission in patient forebrain neurons in vitro and observed that nonremitter patient-derived neurons displayed serotonin-induced hyperactivity downstream of upregulated excitatory serotonergic receptors, in contrast to what is seen in healthy and remitter patient-derived neurons. Our data suggest that postsynaptic forebrain hyperactivity downstream of SSRI treatment may play a role in SSRI resistance in MDD.

Differentiation of Inflammation-Responsive Astrocytes from Glial Progenitors Generated from Human Induced Pluripotent Stem Cells.

Astrocyte dysfunction and neuroinflammation are detrimental features in multiple pathologies of the CNS. Therefore, the development of methods that produce functional human astrocytes represents an advance in the study of neurological diseases. Here we report an efficient method for inflammation-responsive astrocyte generation from induced pluripotent stem cells (iPSCs) and embryonic stem cells. This protocol uses an intermediate glial progenitor stage and generates functional astrocytes that show levels of glutamate uptake and calcium activation comparable with those observed in human primary astrocytes. Stimulation of stem cell-derived astrocytes with interleukin-1ß or tumor necrosis factor α elicits a strong and rapid pro-inflammatory response. RNA-sequencing transcriptome profiling confirmed that similar gene expression changes occurred in iPSC-derived and primary astrocytes upon stimulation with interleukin-1ß. This protocol represents an important tool for modeling in-a-dish neurological diseases with an inflammatory component, allowing for the investigation of the role of diseased astrocytes in neuronal degeneration.

Immuno-Chromatographic Wicking Assay for the Rapid Detection of Chikungunya Viral Antigens in Mosquitoes (Diptera: Culicidae).

The outbreak of disease caused by chikungunya virus (CHIKV) in 2006 and the recent spread of this virus to the Americas in 2013 indicate the potential for this virus to spread and cause significant disease. However, there are currently no accurate and reliable field-usable, diagnostic methods to provide critical, real-time information for early detection of CHIKV within the vector populations in order to implement appropriate vector control and personal protective measures. In this article, we report the ability of an immuno-chromatographic assay developed by VecTOR Test Systems Inc. to detect CHIKV in a pool of female Aedes mosquitoes containing a single CHIKV-infected mosquito. The CHIKV dipstick assay was simple to use, did not require a cold chain, and provided clear results within 1 h. It was highly specific and did not cross-react with samples spiked with a variety of other alpha, bunya, and flaviviruses. The CHIKV assay can provide real-time critical information on the presence of CHIKV in mosquitoes to public health personnel. Results from this assay will allow a rapid threat assessment and the focusing of vector control measures in high-risk areas.

Immuno-chromatographic wicking assay for the rapid detection of dengue viral antigens in mosquitoes (Diptera: Culicidae).

There is a threat for dengue virus (DENV) reemergence in many regions of the world, particularly in areas where the DENV vectors, Aedes aegypti (L.) and Aedes albopictus (Skuse), are readily available. However, there are currently no accurate and reliable diagnostic methods to provide critical, real-time information for early detection of DENV within the vector populations to implement appropriate vector control and personal protective measures. In this article, we report the ability of an immuno-chromatographic assay developed by VecTOR Test Systems Inc. to detect DENV in a pool of female Aedes mosquitoes infected with any of the four viral serotypes. The DENV dipstick assay was simple to use, did not require a cold chain, and provided clear results within 30 min. It was highly specific and did not cross-react with samples spiked with West Nile, yellow fever, Japanese encephalitis, Rift Valley fever, chikungunya, Venezuelan equine encephalomyelitis, Ross River, LaCrosse, or Caraparu viruses. The DENV assay can provide real-time critical information on the presence of DENV in mosquitoes to public health personnel. Results from this assay will allow a rapid threat assessment and the focusing of vector control measures in high-risk areas.

Field evaluation of a wicking assay for the rapid detection of Rift Valley fever viral antigens in mosquitoes.

Rift Valley fever virus (RVFV) causes outbreaks of severe disease in domestic ungulates as well as humans in Africa. There is a concern that outbreaks of Rift Valley fever may continue and that this virus may spread into regions where it had not previously been detected. Surveillance and rapid detection are critical to the initiation of an effective disease control program. Here we report on the field evaluation in Kenya of the VectorTest RVFV antigen assay, modeled on the VecTest assay for West Nile virus. The dipsticks provided results in <20 min, were easy to use, and did not require a laboratory with containment facilities. Although none of the field-collected mosquitoes were infected with RVFV, the dipstick provided a clear positive result with pools of field-collected mosquitoes spiked with a single positive, irradiated (to inactivate any infectious virus) mosquito. Similarly, the dipstick was able to detect virus from pools of mosquitoes captured during the RVFV outbreak in 2007. The RVFV dipstick assay was highly specific with only a single weak false positive out of 266 pools tested (specificity > 99.6%). The RVFV assay can provide a rapid, safe, easy-to-use preliminary test to alert public health personnel to the presence of RVFV in mosquitoes in a given area. Results from this assay will allow for more rapid medical threat assessments and the focusing of vector control measures on high-risk areas.