Marcin Skoreński

Anti-herpesvirus agents: a patent and literature review (2003 to present)

Introduction: The standard therapy used to treat herpesvirus infections is based on the application of DNA polymerase inhibitors such as ganciclovir or aciclovir. Unfortunately, all of these compounds exhibit relatively high toxicity and the mutation of herpesviruses results in the appearance of new drug-resistant strains. Consequently, there is a great need for the development of new, effective and safe anti-herpesvirus agents that employ different patterns of therapeutic action at various stages of the virus life cycle. Areas covered: Patents and patent applications concerning the development of anti-herpesvirus agents displaying different mechanisms of action that have been published since 2003 are reviewed. In addition, major discoveries in this field that have been published in academic papers have also been included. Expert opinion: Among all the anti-herpesvirus agents described in this article, the inhibitors of viral serine protease seem to present one of the most effective/promising therapeutics. Unfortunately, the practical application of these antiviral agents has not yet been proven in any clinical trials. Nevertheless, the dynamic and extensive work on this subject gives hope that a new class of anti-herpesvirus agents aimed at the enzymatic activity of herpesvirus serine protease may be developed.

Substrate profiling of Zika virus NS2B-NS3 protease.

Zika virus (ZIKV), isolated from macaques in Uganda in 1947, was not considered to be a dangerous human pathogen. However, this view has recently changed as ZIKV infections are now associated with serious pathological disorders including microcephaly and Guillain–Barré syndrome. Similar to other viruses in the Flaviviridae family, ZIKV expresses the serine protease NS3 which is responsible for viral protein processing and replication. Herein, we report the expression of an active NS3pro domain fused with the NS2B cofactor (NS2BLNNS3pro) in a prokaryotic expression system and profile its specificity for synthesized FRET‐type substrate libraries. Our findings pave way for screening potential intracellular substrates of NS3 and for developing specific inhibitors of this ZIKV protease.

Phosphonic analogues of glutamic acid as irreversible inhibitors of Staphylococcus aureus endoproteinase GluC: an efficient synthesis and inhibition of the human IgG degradation.

Endoproteinase GluC (V8 protease) is one of many virulence factors released by the Staphylococcus aureus species in vivo. The V8 protease is able to hydrolyze some serpins and all classes of mammalian immunoglobulins. The application of specific and potent inhibitors of V8 protease may lead to the development of new antibacterial agents. Herein, we present the synthesis and the inhibitory properties of novel peptidyl derivatives of a phosphonic glutamic acid analogue. One of the compounds Boc-Phe-Leu-Glu(P)(OC(6)H(4))(2) displayed an apparent second-order inhibition rate value of 8540 M(-1)s(-1). The Boc-Phe-Leu-Glu(P)(OC(6)H(4))(2) compound with the highest inhibitory potency showed the ability to prevent V8-mediated human IgG proteolysis in vitro.

Method for generation of peptide‐specific igy antibodies directed to Staphylococcus aureus extracellular fibrinogen binding protein epitope

The IgY antibodies offer an attractive alternative to mammalian IgGs in research, diagnosis and medicine. The isolation of immunoglobulin Y from the egg yolks is efficient and economical, causing minimal suffering to animals. Here we present the methodology for the production of IgY antibodies specific to Staphylococcus aureus fibrinogen binding protein (Efb) and its peptidyl epitope (spanning residues 127–140). The Efb is an extracellular, adhesion protein which binds both human fibrinogen and complement C3 protein thus contributing to the high infectious potential of this pathogen. The selected epitope of Efb protein is responsible for the interaction with C3. The immunochemical characterization of both anti‐Efb and epitope‐specific IgY antibodies revealed their similar avidity, titer, and reactivity profile, although some differences in the hens immune response to administered antigens is discussed.

Exploiting the S4–S5 Specificity of Human Neutrophil Proteinase 3 to Improve the Potency of Peptidyl Di(chlorophenyl)-phosphonate Ester Inhibitors: A Kinetic and Molecular Modeling Analysis

The neutrophilic serine protease proteinase 3 (PR3) is involved in inflammation and immune response and thus appears as a therapeutic target for a variety of infectious and inflammatory diseases. Here we combined kinetic and molecular docking studies to increase the potency of peptidyl-diphenyl phosphonate PR3 inhibitors. Occupancy of the S1 subsite of PR3 by a nVal residue and of the S4-S5 subsites by a biotinylated Val residue as obtained in biotin-VYDnVP(O-C6H4-4-Cl)2 enhanced the second-order inhibition constant kobs/[I] toward PR3 by more than 10 times ( kobs/[I] = 73000 ± 5000 M-1 s-1) as compared to the best phosphonate PR3 inhibitor previously reported. This inhibitor shows no significant inhibitory activity toward human neutrophil elastase and resists proteolytic degradation in sputa from cystic fibrosis patients. It also inhibits macaque PR3 but not the PR3 from rodents and can thus be used for in vivo assays in a primate model of inflammation.

Phosphonate inhibitors of West Nile virus NS2B/NS3 protease

Abstract West Nile virus (WNV) is a member of the flavivirus genus belonging to the Flaviviridae family. The viral serine protease NS2B/NS3 has been considered an attractive target for the development of anti-WNV agents. Although several NS2B/NS3 protease inhibitors have been described so far, most of them are reversible inhibitors. Herein, we present a series of α-aminoalkylphosphonate diphenyl esters and their peptidyl derivatives as potent inhibitors of the NS2B/NS3 protease. The most potent inhibitor identified was Cbz-Lys-Arg-(4-GuPhe)P(OPh)2 displaying Ki and k2/Ki values of 0.4 µM and 28 265 M−1s−1, respectively, with no significant inhibition of trypsin, cathepsin G, and HAT protease.

One Step Beyond: Design of Substrates Spanning Primed Positions of Zika Virus NS2B-NS3 Protease

Although the mosquito-borne Zika virus was discovered in the late 1940s of the 20th century, for years it was neglected, as the disease in humans was rare and relatively mild. Viral NS2B-NS3 protease is essential for virus replication, and except for maturation of viral proteins, it also modulates the infection microenvironment to facilitate virus invasion. Here, we report the combinatorial chemistry approach for the synthesis of internally quenched substrates of the Zika virus NS2B-NS3 protease that were optimized in prime positions of the peptide chain. Final substrate ABZ-Val-Lys-Lys-Arg-Ala-Ala-Trp-Tyr(3-NO2)-NH2 displays an excellent kinetic parameter (k cat/K M reaching nearly 1.26 × 108 M-1 × s-1), which is over 10 times greater than previously reported (7.7 × 106 M-1 × s-1) substrate. Moreover, it was found to be selective over West Nile virus protease.

Development of novel inhibitors targeting NS3/4A protease of hepatitis C virus

Infections due to Hepatitis B and Hepatitis C viruses are significant health problems around the globe, Nigeria inclusive. Asymptomatic Hepatitis B and C infections are common and when occurring in pregnancy can be transmitted to the new born. To determine the prevalence rate of asymptomatic hepatitis B and C infections among pregnant women, 406 pregnant women attending antenatal clinic at University Health centre and Our Lady of Apostle hospital, all in Jos, Plateau State were recruited for the study. The study was also carried out to determine whether liver aminotransferases and serum albumin can be affected by hepatitis infection during pregnancy. Demographic and past clinical histories were obtained using a questionnaire. Serum samples from each study subject were tested using third-generation enzyme immunoassay kits for hepatitis B surface antigen (HBsAg) and antibodies against hepatitis C (HCV). Serum Alanine Aminotransferase (ALT) and serum aspartate aminotransferase (AST) activities were also estimated in all subjects using Reitman-Frankel method. Also serum albumin was measured in all subjects using Bromocresol green (BCG) method by Teitz. The results showed that 10.0% and 1.2% of the 406 blood samples tested positive on HBV and HCV, respectively. Furthermore, 1.2% of the 406 blood samples tested positive with both HBV and HCV. The mean AST levels for HBsAg negative and positive subjects were 10.55 ± 0.05 and 12.16 ± 0.29, respectively while the mean ALT levels were 5.54 ± 0.005 and 8.01 ± 0.01, respectively. The mean AST for anti-HCV negative and positive subject were 10.67 ± 0.01 and 9.01 ± 0.05, respectively while ALT were 5.71 ± 0.01 and 4.01 ± 0.05, respectively. There was a significant increase in levels of AST and ALT between the HBsAg positive and negative pregnant subjects (P < 0.05). Furthermore, the mean serum albumin level for HBsAg positive and negative pregnant subjects were 30.60 ± 2.75 and 35.58 ± 3.82, respectively. Also, the mean albumin level for HCV positive and negative pregnant subjects were 28.5 ± 2.12 and 35.55 ± 3.7, respectively. There was a significant increase in albumin level between HBsAg and HCV positive and negative pregnant subjects (P < 0.05). HBV and HCV infection can be present in pregnant women and can alter liver aminotransferases and serum albumin. Routine screening of pregnant women for HBV and HCV should be instituted in order to detect infection early and prevent or reduce vertical or prenatal transmission. Correspondence to: Onwuiri FC, Department of Plant Science and Technology, Applied Microbiology Unit, University of Jos, Nigeria, Tel: +2348065302804; E-mail: faconwuliri@yahoo.com Received: March 22, 2017; Accepted: April 19, 2017; Published: April 22, 2017 Introduction Viral hepatitis is the inflammation of the liver caused by infection with hepatitis viruses. Infection with hepatitis B virus or hepatitis C virus are public health problems and are highly endemic in SubSaharan Africa [1,2]. Worldwide, there are about 350 million HBV carriers [3]. HBV and HCV infections are major causes of morbidity and mortality. Hepatits B virus is a DNA virus of the family hepadneviridae and the causative agent of hepatitis B infection [4]. It is 50-100 times more infectious than HIV and 10 times more infectious than hepatitis C. Many carriers do not realize they are infected with the virus, thus it is referred to as a ‘silent killer’ [5]. Hepatitis C virus (HCV) is an RNA virus of the flaviviridae family and appears to have humans and chimpazees as the species susceptible to its infection [6]. About 170 million people are infected with HCV worldwide [7]. Both viruses are transmitted through contact with infected blood, sexual intercourse and vertical transmission (mother-to-child) [8]. Maternal mortality has been shown to increase in pregnant women with liver cirrhosis. HBV and HCV account for a substantial portion of liver diseases worldwide and infected individuals can remain asymptomatic for decades. However, more than 80% of them become chronic carriers which result in an increased risk of liver cirrhosis, liver cancer and liver failure 20-30 years later. They share similar modes of transmission. Coinfection is not uncommon especially in areas of high prevalence and among people at high risk for parental infection. In Nigeria, the prevalence rate of HBV and HCV in pregnant women differ from one locality to another. Yakasai et, al. [9] reported a prevalence of 7.9% HBsAg in pregnant women in Kano, Nigeria. While Oladeinde et, al. [10] reported a prevalent rate of 8 (2.2%) and 3 (0.8%) of HBV and HCV infections, respectively among pregnant women in Benin city, Nigeria. Co-infection of HBV and HCV seems to result in more severe disease than either infection alone. Globally hepatitis B virus (HBV) infection is the most common form of chronic hepatitis around the world. Chronic carriers can Onwuiri FC (2017) Prevalence of Hepatitis B Virus (Hbv) and Hepatitis C Virus (Hcv) and their effects on serum albumin and liver aminotransferases in pregnant women in Jos Volume 1(2): 2-4 Virol Res Rev, 2017 doi: 10.15761/VRR.1000108 continue to transmit the disease for many years, before becoming symptomatic [11]. Together hepatitis B and C represent one of the major threats to global health. Infection occurs very often in early childhood when it is asymptomatic and then lead to the chronic carrier state; chronic HBV infection leads to increase risk for chronic hepatic insufficiency, cirrhosis, and hepatocellular carcinoma (HCC) [11]. In many developed countries (e.g. those in Western Europe and North America) patterns of transmission are different from those in developing countries. The majority of infections in developing countries are transmitted by sexual activity and drug use especially among young adults [12]. Hepatitis B is a major infectious occupational hazard of health worker. Hepatitis B Virus is not spread by contaminated food or water and cannot be spread casually in the work place. Hepatitis B is transmitted through contact with an infected person’s blood, semen or other body fluid. Materials and methods Study area This study was carried out in the University Health Centre (UHC) and Our Lady of Apostle (OLA) hospital, both located in Jos North Local government of Plateau State. University Health Centre is located in the permanent site of University of Jos, and is positioned to take care of the health needs of students, staff and their dependents. Anti-natal care is also given to both staff and students. OLA hospital is located in the heart of the city of Jos being a popular maternity place for different ethnic and religious groups, both urban and rural women use OLA hospital for their antenatal care center. the study was conducted on 406 pregnant women attending ante-natal clinic in UHC and OLA hospitalBackground: The endemicity of Hepatitis B virus (HBV) infection is leveling off in sub-Saharan Africa; it remains at an unacceptable high level (≥8%, to <2%) with global prevalence of 3·61%. The present study assessed the effectiveness of a peer-led HBV prevention education intervention in Usman Danfodiyo University Sokoto, Nigerian on youth’s HBV-related knowledge,attitude,and practices. Methods: In a peer-led single blind randomized controlled community trial conducted between April and December 2015. 390students were selected and randomized into the intervention and control arms, each arm with 195 respondents; five out of 12 faculties were selected using multi-staged random sampling. Four surveys were conducted(baseline, immediately, three and six months using self-administered questionnaire.Analysis of data were conducted using SPSS version 22. Results: The overall response rate during the four survey were 100%, 99.4%, 98.9% and 98.4%for intervention group and 100%, 100%, 99.4%,and 98.9% for the control arm respectively. Hepatitis B- related knowledge, attitude,and practices of the respondents were statistically significant between the intervention and the control arms at immediately, three and six month’s follow-up assessment with no statistical significant difference at baseline assessment (knowledge 14.3%, 66.95%, & 62.7%, HBV-related attitude 23.56%,40.68%, & 46.12% and HBV-related preventive practices 26.14%, 6.53%,& 11.9%). Conclusions: The present study has shown an evident for its effectiveness on HBV-related knowledge, attitude and preventive practice among the undergraduate non-medical and non-veterinary university students of Usman Danfodiyo University Sokoto Nigeria.

Novel peptidyl α-aminoalkylphosphonates as inhibitors of hepatitis C virus NS3/4A protease

Abstract Herein, we describe the synthesis and application of novel phosphonic inhibitors designed to target the NS3/4A protease, which is crucial for the life cycle of hepatitis C virus. We examined the inhibitory potency of our synthesized compounds against two genotypes (1a and 1b) of NS3/4A protease and four mutant strains of HCV. The most potent inhibitors displayed k2/KI values of 79 850 M−1s−1 and 60 850 M−1s−1 against genotype 1a and 1b protease, respectively. Further in vitro evaluation of the most potent inhibitors revealed that vastly reduced HCV replication. Cellular toxicity, plasma stability, reactivity with selected human proteases as well the stability of inhibitor‐protease complex and its intracellular availability are also discussed. Graphical abstract Figure. No caption available. HighlightsThe synthesis of novel irreversible phosphonic inhibitors of HCV NS3/4A protease is described.The inhibitory potency of synthesized compounds has been demonstrated.The selectivity of synthesized compounds has been evaluated.The most potent inhibitor 54R showed k2/Ki value of 79 850 M−1s−1.The obtained inhibitors reduced replication of HCV genotypes 1b and 2a.

Selection of Effective HTRA3 Activators Using Combinatorial Chemistry

Herein, we report selection, synthesis, and enzymatic evaluation of a peptidomimetic library able to increase proteolytic activity of HtrA3 (high temperature requirement A) protease. Iterative deconvolution in solution of synthesized modified pentapeptides yielded two potent HtrA3 activators acting in the micromolar range (HCOO-CH2O-C6H4-OCH2-CO-Tyr-Asn-Phe-His-Asn-OH and HCOO-CH2O-C6H4-OCH2-CO-Tyr-Asn-Phe-His-Glu-OH). Both compounds increased proteolysis of an artificial HtrA3 substrate over 40-fold in a selective manner. On the basis of molecular modeling, the selected compounds bind strongly to the PDZ domain.