Is Gain of Function a Reliable Tool for Establishing Sars-Cov-2 Origin?

The present opinion article, while dealing with the debated origin of “Severe Acute Respiratory Syndrome-Coronavirus-2” (SARS-CoV-2), the betacoronavirus responsible for “Corona Virus Disease-2019” (COVID-19), provides a speculative insight into the so-called “gain of function” (GOF), a process resulting in the acquirement of new phenotypic features on behalf of the viral pathogen. More in detail, a GOF-related phenomenon leading to increased SARS-CoV-2 virulence and/or transmissibility—as clearly exemplified by the “delta” and the “omicron” as well as by other “variants of concern”—would not necessarily imply that viral genetic manipulations made in the laboratory are its exclusive drivers, provided that GOF may also occur as a consequence of a natural selection process. In order to gain a better understanding of SARS-CoV-2 GOF and GOF-associated phenomena, an in-depth knowledge of the complex viral-host interaction dynamics is absolutely needed, while also paying special attention to the human-animal-viral ecological interfaces within an “ad hoc” multidisciplinary, “holistic”, scientific evidence-based and “One Health”-based approach.

An updated review on activated PI3 kinase delta syndrome(APDS)

Activated Phosphoinositide 3-kinase d syndrome(APDS)is a newly recognised primary immunodeficiency disease.It has currently been a hot topic of clinical research and new data are emerging regarding its pathogenesis,clinical manifestations and treatment.Patients with APDS syndrome have significant autoimmune manifestations and lymphoproliferation.It is important to differentiate APDS from the usual polygenic CVID in view of the availability of targeted therapy like mTOR inhibitors such as Rapamycin and selective PI3Kd inhibitors.We provide a comprehensive review on this interesting disorder focusing light on its etiology,genetic research and emerging therapy.

A novel mutation in proprotein convertase subtilisin/kexin type 9 gene leads to familial hypercholesterolemia in a Chinese family

Background Familial hypercholesterolemia （FH） is an autosomal disorder associated with elevated plasma low density lipoprotein （LDL） levels leading to premature coronary heart disease （CHD）. As a result of long-term hyperlipemia, FH patients will present endarterium thickening and atherosclerosis. In the present study we scanned the related gene of a clinically diagnosed autosomal genetic hypercholesterolemia family for the possible mutations and established eukaryotic expression vector of mutation of proprotein convertase subtilisin/kexin type 9 （PCSK9） gene with gene recombination technique to investigate the contributions of the variation on low density lipoprotein receptor （LDL-R） metabolism and function alternation.Methods Mutation detection was conducted for LDL-R, apolipoprotein B100 （apoB100） and PCSK9 gene with nucleotide sequencing in a Chinese FH family. The full-length cDNA of wild type PCSK9 gene （WT-PCSK9） was obtained from Bel-7402. Site mutagenesis was used to establish the recombinant eukaryotic expression vector carrying pathogenic type of PCSK9 gene and the inserted fragment was sequenced. With the blank vector as control, liposome transfection method was used to transfect the Bel-7402 cells with recombinant plasmid. The expression of LDL-R mRNA was examined by RT-PCR. PCSK9 and the expression of LDL-R protein were determined by Western blotting. Results The G→T mutation at the 918 nucleotide of PCSK9 gene resulted in the substitution of the arginine by a serine at the codon 306 of exon 6. After sequencing, it was confirmed that the inserted fragment of established expression vector had correct size and sequence and the mutant was highly expressed in Bel-7402 cells. There was no significant variation in the levels of LDL-R mRNA. LDL-R mature protein was decreased by 57% after the cells were transfected by WT-PCSK9 plasmid. Mature LDL-R was significantly decreased by 12% after the cells were transfected by R306S mutant as evidenced by gray scale scanning, suggesting that the new mutant R306S can significantly decrease the expression of mature LDL-R protein.Conclusions A novel missense mutation of PCSK9 gene, R306S, was found and the eukaryotic expression vectors of mutant and wild-type of PCSK9 gene were established. There was no significant variation in the levels of LDL-R mRNA. The R306S mutation could significantly lead to the decrease of LDL-R mature protein expression, which might be the pathogenic gene of the FH family.