9 research outputs found
Acriflavine, a clinically approved drug, inhibits SARS-CoV-2 and other betacoronaviruses
The COVID-19 pandemic caused by SARS-CoV-2 has been socially and economically devastating. Despite an unprecedented research effort and available vaccines, effective therapeutics are still missing to limit severe disease and mortality. Using high-throughput screening, we identify acriflavine (ACF) as a potent papain-like protease (PLpro) inhibitor. NMR titrations and a co-crystal structure confirm that acriflavine blocks the PLpro catalytic pocket in an unexpected binding mode. We show that the drug inhibits viral replication at nanomolar concentration in cellular models, in vivo in mice and ex vivo in human airway epithelia, with broad range activity against SARS-CoV-2 and other betacoronaviruses. Considering that acriflavine is an inexpensive drug approved in some countries, it may be immediately tested in clinical trials and play an important role during the current pandemic and future outbreaks. 漏 2021 The Author
Analysis of interactions between HCoV-NL63 N protein and host cell proteins
Odkryty w roku 2004 HCoV-NL63 (ang. human coronavirus NL63) powoduje zazwyczaj infekcje g贸rnych lub dolnych dr贸g oddechowych o 艂agodnym przebiegu, niemniej dla dzieci, os贸b starszych lub o os艂abionej odporno艣ci mo偶e przedstawia膰 powa偶ne zagro偶enie dla zdrowia, a nawet 偶ycia.Wirusy s膮 paso偶ytami obligatoryjnie wewn膮trzkom贸rkowymi, wykorzystuj膮cymi liczne procesy kom贸rkowe. W zwi膮zku z tym, dla zrozumienia mechanizm贸w zaka偶enia niezb臋dne jest poznanie interakcji pomi臋dzy bia艂kami wirusowymi oraz kom贸rkowymi. W przypadku koronawirus贸w wa偶n膮 rol臋 w pe艂ni bia艂ko N. Jego podstawow膮 funkcj膮 jest wi膮zanie genomowego RNA, kt贸re nast臋pnie w formie rybonukleoproteiny jest pakowane do wirion贸w. Opr贸cz tego wykazuje ono wiele aktywno艣ci pozwalaj膮cych na modyfikacj臋 maszynerii transkrypcyjnej i translacyjnej w kom贸rce, niezb臋dnych dla wydajnej produkcji bia艂ek wirusowych. Bia艂ko N oddzia艂uje r贸wnie偶 z elementami uk艂adu immunologicznego, uniemo偶liwiaj膮c wykrycie wirusa oraz hamuje apoptoz臋 zaka偶onych kom贸rek.Celem niniejszej pracy by艂o poznanie potencjalnych partner贸w kom贸rkowych bia艂ka N HCoV-NL63, oraz analiza wp艂ywu tych oddzia艂ywa艅 na replikacj臋 wirusa. Pierwsza z dw贸ch zastosowanych metod, polegaj膮ca na transfekcji kom贸rek eukariotycznych plazmidem koduj膮cym bia艂ko N z metk膮, a nast臋pnie immunoprecypitacji kompleks贸w bia艂kowych nie przynios艂a oczekiwanych rezultat贸w, gdy偶 ilo艣膰 wyizolowanych bia艂ek nie by艂a wystarczaj膮ca do ich identyfikacji. Z pomoc膮 drugiej techniki, wykorzystuj膮cej bia艂ko N wyra偶one w systemie prokariotycznym, oraz lizaty kom贸rkowe, uda艂o si臋 zidentyfikowa膰 bia艂ka potencjalnie b臋d膮ce partnerami bia艂ka N. W艣r贸d zidentyfikowanych bia艂ek znalaz艂o si臋 Hsp90, bia艂ko opieku艅cze odpowiedzialne stabilizacj臋 i prawid艂owe fa艂dowanie bia艂ek kom贸rkowych. Wiadomo r贸wnie偶, 偶e bia艂ko to uczestniczy w replikacji niekt贸rych wirus贸w, jednak z przeprowadzonych bada艅 wynika, 偶e zale偶no艣膰 ta nie wyst臋puje w przypadku HCoV-NL63.Discovered in 2004, HCoV-NL63 in majority of cases causes common cold in healthy adults. However, it can pose a serious threat to young children, the elderly and immunocompromised individuals.As viruses are obligatory intracellular parasites, in order to fully understand the process of virus replication it is essential to identify which cellular proteins are required for infection. The coronaviral nucleocapsid (N) protein is an important structural protein that, by binding to the genomic RNA, forms virus core, which is further assembled into new virus particles. Interestingly, this protein was assigned with a number of other functions, enabling the virus to hijack the cellular transcription and translation machinery. The N protein also interacts with the immune system, e.g., helping the virus to evade recognition and prevents apoptosis of infected cells.The aim of this work was to identify cellular proteins interacting with HCoV-NL63 N protein, and to further analyze these interactions. The first method, based on eukaryotic cell transfection with a plasmid coding for the tagged N protein, did not bring expected results, due to low expression levels not allowing for identification with mass spectrometry. The second approach, employing the N protein expressed in E.coli and cellular lysates, led to identification of potential cellular partners of HCoV-NL63 N protein.The most intriguing of them was Hsp90, a chaperone protein, responsible for folding and maturation of many cellular proteins. This protein is also known to be important for replication of some viral species, but conducted experiments showed that HCoV-NL63 replication is Hsp90 independent
Novel peptidyl \alpha-aminoalkylphosphonates as inhibitors of hepatitis C virus NS3/4A protease
Inhibition of herpes simplex viruses by cationic dextran derivatives
Human herpesviruses are among the
most prevalent pathogens and
currently there are no drugs available that could cure diseases induced
by them. The most widely utilized antiherpes drugs, acyclovir and
its derivatives, have serious limitations, such as low bioavailability
and severe side effects. The current paper reports on the synthesis
and characterization of cationic dextran derivatives (DEX<sub><i>x</i></sub>DS<sub><i>y</i></sub>) of various molecular
weights and various degrees of substitution with ammonium groups,
which were tested as antiherpes agents. DEX<sub><i>x</i></sub>DS<sub><i>y</i></sub> showed high effectiveness against
HSV-1 and HSV-2 viruses, as found using a variety of techniques. Importantly,
no toxicity was observed for these compounds in the range of active
concentrations, demonstrating their potential as antivirals. The mechanism
of action of DEX<sub><i>x</i></sub>DS<sub><i>y</i></sub> was assessed. We hypothesize that they may limit virus transmission,
as extensive examination showed that they hamper the interaction between
the virus and the cellular attachment receptor
Highly effective and safe polymeric inhibitors of herpes simplex virus in vitro and in vivo
Refolding of lid subdomain of SARS-CoV-2聽nsp14 upon nsp10 interaction releases exonuclease activity
During RNA replication, coronaviruses require proofreading to maintain the integrity of their large genomes. Nsp14 associates with viral polymerase complex to excise the mismatched nucleotides. Aside from the exonuclease activity, nsp14 methyltransferase domain mediates cap methylation, facilitating translation initiation and protecting viral RNA from recognition by the innate immune sensors. The nsp14 exonuclease activity is modulated by a protein co-factor nsp10. While the nsp10/nsp14 complex structure is available, the mechanistic basis for nsp10-mediated modulation remains unclear in the absence of the nsp14 structure. Here, we provide a crystal structure of nsp14 in an apo-form. Comparative analysis of the apo- and nsp10-bound structures explain the modulatory role of the co-factor protein and reveal the allosteric nsp14 control mechanism essential for drug discovery. Further, the flexibility of the N-terminal lid of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nsp14 structure presented in this study rationalizes the recently proposed idea of nsp14/nsp10/nsp16 ternary complex