The emerging role of furin in neurodegenerative and neuropsychiatric diseases.

Furin is an important mammalian proprotein convertase that catalyzes the proteolytic maturation of a variety of prohormones and proproteins in the secretory pathway. In the brain, the substrates of furin include the proproteins of growth factors, receptors and enzymes. Emerging evidence, such as reduced FURIN mRNA expression in the brains of Alzheimer's disease patients or schizophrenia patients, has implicated a crucial role of furin in the pathophysiology of neurodegenerative and neuropsychiatric diseases. Currently, compared to cancer and infectious diseases, the aberrant expression of furin and its pharmaceutical potentials in neurological diseases remain poorly understood. In this article, we provide an overview on the physiological roles of furin and its substrates in the brain, summarize the deregulation of furin expression and its effects in neurodegenerative and neuropsychiatric disorders, and discuss the implications and current approaches that target furin for therapeutic interventions. This review may expedite future studies to clarify the molecular mechanisms of furin deregulation and involvement in the pathogenesis of neurodegenerative and neuropsychiatric diseases, and to develop new diagnosis and treatment strategies for these diseases.

Establishment of the first Chinese national standard for protein subunit SARS-CoV-2 vaccine.

A reference standard is needed for quality control of protein subunit SARS-CoV-2 vaccines to meet urgent domestic needs. The Chinese National Institutes for Food and Drug Control (NIFDC) launched a project to establish the first reference material for the protein subunit SARS-CoV-2 vaccine to be used for calibration of antigen testing. The potency and stability of the national candidate standard (CS) were determined by collaborative calibration, and accelerated and freeze-thaw degradation studies. Moreover, a suitability study of the CS was performed. Eight laboratories in mainland China were asked to detect antigen content of CS using a common validated enzyme-linked immunosorbent assay (ELISA) kit established by NIFDC and in-house kits in the collaborative study. Six laboratories returned valid results, which established that the antigen content of the CS was 876,938 YU/mL, with good agreement across laboratories. In the suitability study, the CS exhibited excellent parallelism and a linear relationship with four samples produced by different expression systems and target proteins. In addition, good stability in the accelerated and freeze-thaw degradation study was observed. In conclusion, the CS was approved by the Biological Product Reference Standards Sub-Committee of the National Drug Reference Standards Committee as the first Chinese national standard for determining antigen content of protein subunit SARS-CoV-2 vaccines, with an assigned antigen content of 877,000 U/mL (Lot. 300050-202101). This standard will contribute to a standardized assessment of protein subunit SARS-CoV-2 vaccine in China and may provide experience for developing reference materials for antigen content detection of SARS-CoV-2 vaccine in other countries.

Research Note: Rapid detection of avian infectious laryngotracheitis virus with real-time fluorescence-based recombinase-aided amplification.

In this study, specific primers and fluorescent probes were designed to target the thymidine kinase (TK) gene sequence of avian infectious laryngotracheitis virus (ILTV). Through specificity and sensitivity tests, a real-time fluorescence-based recombinase-aided amplification (RF-RAA) method for detecting ILTV was established. The results showed that the method was specific and could be used to accurately detect ILTV, and there was no cross-reaction with Newcastle disease virus (NDV), avian influenza virus (AIV), or infectious bronchitis virus (IBV). Real-time fluorescence-based recombinase-aided amplification had high sensitivity, and the lowest detectable limit (LDL) for ILTV could reach 10 copies/µL, 1,000 times more sensitive than conventional PCR (104 copies/µL), to rival that of real-time fluorescence-based quantitative PCR (RFQ-PCR) (10 copies/µL). This method and RFQ-PCR were used to detect 96 samples of chicken throat swabs with ILT initially diagnosed in clinic from the north of China, and the coincidence rate of the 2 methods was 100%. The RF-RAA reaction required only 20-30 minutes to completing, and its sensitivity was much higher than that of conventional PCR. Real-time fluorescence-based recombinase-aided amplification is similar to RFQ-PCR and has the advantages of specificity, sensitivity, and high efficiency, so it is suitable for early clinical detection and epidemiological investigation of ILTV.

Reverse transcription recombinase-aided amplification assay combined with a lateral flow dipstick for detection of avian infectious bronchitis virus

The study was conducted to develop a specific, simple, and sensitive method for diagnosis of avian infectious bronchitis virus (IBV). In this experiment, the selected downstream primer was labeled with biotin and the 5' end of RAA probe was labeled with FAM by reverse transcription recombinase-aided amplification (RT-RAA) combined with lateral flow dipstick (LFD). A RT-RAA-LFD assay that could be used for detection of IBV was established after optimization of RT-RAA reaction time, reaction temperature, and primer concentration. This method did not need reverse transcription of IBV template under isothermal condition (37degreesC), the amplification of target gene fragments could be completed within only 24 min, and the amplification products could be visually observed and determined by LFD within 3 min. The specificity test demonstrated that there was no cross reaction with the nucleic acids of other similar common pathogens. The lowest detectable limit for IBV was 10 sup 2 /sup copies/muL, and this method was 100 times more sensitive than conventional PCR (10 sup 4 /sup copies/muL), as verified by sensitivity test. The results showed that RT-RAA-LFD assay with strong specificity and high sensitivity was simple and easy to operate, and could be used for rapid detection of IBV in clinical diagnosis.