1.Development of a Laboratory-safe and Low-cost Detection Protocol for SARS-CoV-2 of the Coronavirus Disease 2019(COVID-19)
Joungha WON ; Solji LEE ; Myungsun PARK ; Tai Young KIM ; Mingu Gordon PARK ; Byung Yoon CHOI ; Dongwan KIM ; Hyeshik CHANG ; Won Do HEO ; V. Narry KIM ; C. Justin LEE
Experimental Neurobiology 2020;29(5):402-402
2.Development of a Laboratory-safe and Low-cost Detection Protocol for SARS-CoV-2 of the Coronavirus Disease 2019 (COVID-19)
Joungha WON ; Solji LEE ; Myungsun PARK ; Tai Young KIM ; Mingu Gordon PARK ; Byung Yoon CHOI ; Dongwan KIM ; Hyeshik CHANG ; V. Narry KIM ; C. Justin LEE
Experimental Neurobiology 2020;29(2):107-119
The severe acute respiratory coronavirus 2 (SARS-CoV-2), which emerged in December 2019 in Wuhan, China, has spread rapidly to over a dozen countries. Especially, the spike of case numbers in South Korea sparks pandemic worries. This virus is reported to spread mainly through personto- person contact via respiratory droplets generated by coughing and sneezing, or possibly through surface contaminated by people coughing or sneezing on them. More critically, there have been reports about the possibility of this virus to transmit even before a virus-carrying person to show symptoms. Therefore, a low-cost, easy-access protocol for early detection of this virus is desperately needed. Here, we have established a real-time reverse-transcription PCR (rtPCR)-based assay protocol composed of easy specimen self-collection from a subject via pharyngeal swab, Trizolbased RNA purification, and SYBR Green-based rtPCR. This protocol shows an accuracy and sensitivity limit of 1-10 virus particles as we tested with a known lentivirus. The cost for each sample is estimated to be less than 15 US dollars. Overall time it takes for an entire protocol is estimated to be less than 4 hours. We propose a cost-effective, quick-and-easy method for early detection of SARS-CoV-2 at any conventional Biosafety Level II laboratories that are equipped with a rtPCR machine. Our newly developed protocol should be helpful for a first-hand screening of the asymptomatic virus-carriers for further prevention of transmission and early intervention and treatment for the rapidly propagating virus.
3.Unaltered Tonic Inhibition in the Arcuate Nucleus of Diet-induced Obese Mice
Moonsun SA ; Jung Moo LEE ; Mingu Gordon PARK ; Jiwoon LIM ; Jong Min JOSEPH KIM ; Wuhyun KOH ; Bo-Eun YOON ; C. Justin LEE
Experimental Neurobiology 2022;31(3):147-157
The principal inhibitory transmitter, γ-aminobutyric acid (GABA), is critical for maintaining hypothalamic homeostasis and released from neurons phasically, as well as from astrocytes tonically. Although astrocytes in the arcuate nucleus (ARC) of the hypothalamus are shown to transform into reactive astrocytes, the tonic inhibition by astrocytic GABA has not been adequately investigated in diet-induced obesity (DIO). Here, we investigated the expression of monoamine oxidase- B (MAOB), a GABA-synthesizing enzyme, in reactive astrocytes in obese mice. We observed that a chronic high-fat diet (HFD) significantly increased astrocytic MAOB and cellular GABA content, along with enhanced hypertrophy of astrocytes in the ARC. Unexpectedly, we found that the level of tonic GABA was unaltered in chronic HFD mice using whole-cell patch-clamp recordings in the ARC. Furthermore, the GABA-induced current was increased with elevated GABA A receptor α5 (GABRA5) expression. Surprisingly, we found that a nonselective GABA transporter (GAT) inhibitor, nipecotic acid (NPA)-induced current was significantly increased in chronic HFD mice. We observed that GAT1 inhibitor, NO711-induced current was significantly increased, whereas GAT3 inhibitor, SNAP5114-induced current was not altered. The unexpected unaltered tonic inhibition was due to an increase of GABA clearance in the ARC by neuronal GAT1 rather than astrocytic GAT3. These results imply that increased astrocytic GABA synthesis and neuronal GABA A receptor were compensated by GABA clearance, resulting in unaltered tonic GABA inhibition in the ARC of the hypothalamus in obese mice. Taken together, GABA-related molecular pathways in the ARC dynamically regulate the tonic inhibition to maintain hypothalamic homeostasis against the HFD challenge.