Identification of C270 as a novel site for allosteric modulators of SARS-CoV-2 papain-like protease

The papain-like protease (PLpro) in coronavirus is one of key cysteine proteases responsible for the proteolytic processing of viral polyproteins, and plays an important role in dysregulation of host immune response. PLpro is a promising therapeutic target with a major challenge in inhibitor design due to the restricted S1/S2 sites for two consecutive glycine of substrates. Here we reported the discovery of two activators of the SARS-CoV-2 PLpro from a biochemical screening, and the identification of the unique residue, C270, as an allosteric and covalent regulation site for the activators. This site was also specifically modified by glutathione oxidized, resulting in the S-glutathionylation and activation of the protease. Furthermore, one compound was found to allosterically inhibit the protease by covalent binding to this crucial site. Together, these results elucidated an unrevealed molecular mechanism for allosteric modulation of the proteases activity, and provided a new strategy for discovery of allosteric inhibitors of the SARS-CoV-2 PLpro.

Discovery of baicalin and baicalein as novel, natural product inhibitors of SARS-CoV-2 3CL protease in vitro

Human infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cause coronavirus disease 19 (COVID-19) and there is currently no cure. The 3C-like protease (3CLpro), a highly conserved protease indispensable for replication of coronaviruses, is a promising target for development of broad-spectrum antiviral drugs. To advance the speed of drug discovery and development, we investigated the inhibition of SARS-CoV-2 3CLpro by natural products derived from Chinese traditional medicines. Baicalin and baicalein were identified as the first non-covalent, non-peptidomimetic inhibitors of SARS-CoV-2 3CLpro and exhibited potent antiviral activities in a cell-based system. Remarkably, the binding mode of baicalein with SARS-CoV-2 3CLpro determined by X-ray protein crystallography is distinctly different from those of known inhibitors. Baicalein is perfectly ensconced in the core of the substrate-binding pocket by interacting with two catalytic residues, the crucial S1/S2 subsites and the oxyanion loop, acting as a "shield" in front of the catalytic dyad to prevent the peptide substrate approaching the active site. The simple chemical structure, unique mode of action, and potent antiviral activities in vitro, coupled with the favorable safety data from clinical trials, emphasize that baicalein provides a great opportunity for the development of critically needed anti-coronaviral drugs.

Structural Basis for the Inhibition of the RNA-Dependent RNA Polymerase from SARS-CoV-2 by Remdesivir

The pandemic of Corona Virus Disease 2019 (COVID-19) caused by SARS-CoV-2 has become a global crisis. The replication of SARS-CoV-2 requires the viral RNA-dependent RNA polymerase (RdRp), a direct target of the antiviral drug, Remdesivir. Here we report the structure of the SARS-CoV-2 RdRp either in the apo form or in complex with a 50-base template-primer RNA and Remdesivir at a resolution range of 2.5-2.8 [A]. The complex structure reveals that the partial double-stranded RNA template is inserted into the central channel of the RdRp where Remdesivir is incorporated into the first replicated base pair and terminates the chain elongation. Our structures provide critical insights into the working mechanism of viral RNA replication and a rational template for drug design to combat the viral infection.

Analysis of urodynamics in elderly male patients with indwelling urinary catheterization / 中华老年医学杂志

Objective@#To investigate clinical characteristics of urodynamics in elderly male patients with indwelling urinary catheterization.@*Methods@#Clinical urodynamics of 497 male patients with indwelling urinary catheterization aged 60 years and over from December 2010 to April 2019 in our center were retrospectively analyzed and divided into 3 groups: 60-69-year-old group(n=114), 70-79-year-old group(n=220), and 80-111-year-old group(n=163). According to the catheter indwelling time, the patients were divided into 3 groups: 1-2 weeks group(n=262), 2-4 weeks group(n=47)and over 4 weeks group(n=188). The cause of indwelling urinary catheterization, bladder outlet obstruction, acontractile detrusor and other indicators were observed.@*Results@#The main cause of indwelling urinary catheterization in elderly men was acute urinary retention(55.1%, 274 cases), in that the most common diagnosis was benign prostatic hyperplasia(90.3%, 449 cases). No statistically significant difference in the different catheter indwelling time-related urodynamics between the different age groups was found(χ2=1.606, 0.199 and 2.477, all P>0.05). There were statistically significant differences both in the incidences of bladder outlet obstruction between the 1-2 weeks vs.2-4 weeks vs.over 4 weeks groups[56.9%(149/262)vs.55.3%(26/47) vs.42.6%(80/188), χ2=9.315, P<0.05)], and in the incidences of acontractile detrusor between the 1-2 weeks vs.2-4 weeks vs.over 4 weeks groups[15.6%(41/262)vs.12.8%(6/47)vs.29.8%(56/188), χ2=15.319, all P<0.05)]. There was no statistically significant difference in catheter indwelling time-related urodynamics between two groups with normal detrusor muscle function and weak detrusor muscle function(P>0.05). Clinical urodynamics had no statistically significant in different age groups(P>0.05).@*Conclusions@#Bladder outlet obstruction is the main cause of indwelling urinary catheterization in elderly men.Urodynamic examination can be performed 1-2 weeks after indwelling urinary catheterization.Age has no significant effect on the catheter indwelling time-related urodynamics.The duration of indwelling urinary catheterization has little effect on the urodynamic diagnosis in patients with normal or weak detrusor muscle contractile strength.The elderly patients may have acontractile detrusor if the duration of indwelling urinary catheterization is more than 4 weeks.

Analysis of urodynamics in elderly male patients with indwelling urinary catheterization / 中华老年医学杂志

Objective To investigate clinical characteristics of urodynamics in elderly male patients with indwelling urinary catheterization.Methods Clinical urodynamics of 497 male patients with indwelling urinary catheterization aged 60 years and over from December 2010 to April 2019 in our center were retrospectively analyzed and divided into 3 groups:60-69-year old group(n=114),70-79-year-old group (n =220),and 80-111-year-old group (n =163).According to the catheter indwelling time,the patients were divided into 3 groups:1-2 weeks group(n=262),2 4 weeks group(n=47)and over 4 weeks group (n =188).The cause of indwelling urinary catheterization,bladder outlet obstruction,acontractile detrusor and other indicators were observed.Results The main cause of indwelling urinary catheterization in elderly men was acute urinary retention(55.1％,274 cases),in that the most common diagnosis was benign prostatic hyperplasia(90.3％,449 cases).No statistically significant difference in the different catheter indwelling time related urodynamics between the different age groups was found(x2 =1.606,0.199 and 2.477,all P＞0.05).There were statistically significant differences both in the incidences of bladder outlet obstruction between the 1-2 weeks vs.2-4 weeks vs.over 4 weeks groups [56.9％ (149/262) vs.55.3％ (26/47) vs.42.6％ (80/188),x2=9.315,P＜0.05)],and in the incidences of acontractile detrusor between the 1-2 weeks vs.2-4 weeks vs.over 4 weeks groups[15.6％ (41/262)vs.12.8％(6/47)vs.29.8％ (56/188),x2 =15.319,all P＜ 0.05)].There was no statistically significant difference in catheter indwelling time-related urodynamics between two groups with normal detrusor muscle function and weak detrusor muscle function(P＞0.05).Clinical urodynamics had no statistically significant in different age groups (P＞0.05).Conclusions Bladder outlet obstruction is the main cause of indwelling urinary catheterization in elderly men.Urodynamic examination can be performed 1-2 weeks after indwelling urinary catheterization.Age has no significant effect on the catheter indwelling time-related urodynamics.The duration of indwelling urinary catheterization has little effect on the urodynamic diagnosis in patients with normal or weak detrusor muscle contractile strength.The elderly patients may have acontractile detrusor if the duration of indwelling urinary catheterization is more than 4 weeks.

Neuronix enables continuous, simultaneous neural recording and electrical microstimulation.

This paper reports a novel neurotechnology (Neuronix) and its validation through experiments. It is a miniature system-on-chip (SoC) that allows recording with simultaneous electrical microstimulation. This function has not been demonstrated before and enables precise, closed-loop neuromodulation. Neuronix represents recent advancement in brain technology and applies to both animal research and clinical applications.

Effect of WIN55,212-2 on the Expression of PGE_2 in Cultured Bovine Trabecular Meshwork Cells / 中国中医药信息杂志

Objective To study the effect of WIN55,212-2 on the expression of PGE2 in cultured bovine trabecular meshwork cells(TMCs) and discuss its mechanism of reducing the intraocular pressure.Methods TMCs were obtained through the cultured tissue,bovine TMCs were prmiarily cultured and subcultured.The third generation bovine TMCs were incubated with different dosages of WIN55,212-2 and the supernatant was collected.The concentration of PGE2 in the medium was measured by ELISA method.PGE2mRNA in TMCs was analyzed by RT-PCR.Result PGE2 in the supernatant and PGE2mRNA in TMCs increased depending on the dosages of WIN55,212-2.Conclusion Certain concentration of WIN55,212-2 may promote PGE2 secretion of TMCs,so as to reduce the intraocular pressure.