Type II transmembrane serine proteases as potential target for anti-influenza drug discovery

Optimization of Ketobenzothiazole-Based Type II Transmembrane Serine Protease Inhibitors to Block H1N1 Influenza Virus Replication

Human influenza viruses cause acute respiratory symptoms that can lead to death. Due to the emergence of antiviral drug-resistant strains, there is an urgent requirement for novel antiviral agents and innovative therapeutic strategies. Using the peptidomimetic ketobenzothiazole protease inhibitor RQAR-Kbt (IN-1, aka N-0100) as a starting point, we report how substituting P2 and P4 positions with natural and unnatural amino acids can modulate the inhibition potency toward matriptase, a prototypical type II transmembrane serine protease (TTSP) that acts as a priming protease for influenza viruses. We also introduced modifications of the peptidomimetics N-terminal groups, leading to significant improvements (from μM to nM, 60 times more potent than IN-1) in their ability to inhibit the replication of influenza H1N1 virus in the Calu-3 cell line derived from human lungs. The selectivity towards other proteases has been evaluated and explained using molecular modeling with a crystal structure recently obtained by our group. By targeting host cell TTSPs as a therapeutic approach, it may be possible to overcome the high mutational rate of influenza viruses and consequently prevent potential drug resistance.

Docking study of transmembrane serine protease type 2 inhibitors for the treatment of COVID-19

The recent pandemic development of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its quick national and international spread present a global health emergency. Entry of coronaviruses into the cell depends on binding of the viral spike (S) proteins to host cells receptors, which rely on cell proteases for activation. One of the proteases, transmembrane serine protease type 2 (TMPRSS2) was proven to be crucial for S protein priming. Our research emphasizes on identifying presupposing drug candidates for the TMPRSS2 inhibitors to combat coronavirus disease 2019 (COVID-19). TMPRSS2 homology model is generated by utilizing Modeller9.22, whereas we perform molecular docking with AutoDock Vina. Docking of peptidomimetic inhibitors (inhibitor “92” and inhibitor “50”) and allosteric inhibitors (nafamostat and camostat mesilate) in this study is carried out at the active site of the TMPRSS2 homology model. Known active ligands have low docking score energies varying from −7.6 to −8.7 kcal/mol. The docking study has confirmed peptidomimetic inhibitors bind with the catalytic triad HIS 41 and ASP 90 by strong hydrogen bonding. Allosteric inhibitors block access to the catalytic triad (HIS 41, ASP 90, and SER 186) by forming hydrogen bonds with ASP 180, GLN 183, and GLY 209 in the S1 pocket. This investigation gives an insight into the design and identification of drug repurposing candidates for the management of COVID-19.

Influence of androgen deprivation therapy on the severity of COVID-19 in prostate cancer patients

BACKGROUND

The TMPRSS2 protein has been involved in severe acute respiratory syndrome caused by coronavirus 2 (SARS-CoV-2). The production is regulated by the androgen receptor (AR). It is speculated that androgen deprivation therapy (ADT) may protect patients affected by prostate cancer (PC) from SARS-CoV-2 infection.

METHODS

This is a retrospective study of patients treated for COVID-19 in our institution who had a previous diagnosis of PC. We analyzed the influence of exposure of ADT on the presence of severe course of COVID-19.

RESULTS

A total of 2280 patients were treated in our center for COVID-19 with a worse course of disease in males (higher rates of hospitalization, intense care unit [ICU] admission, and death). Out of 1349 subjects registered in our PC database, 156 were on ADT and 1193 were not. Out of those, 61 (4.52%) PC patients suffered from COVID-19, 11 (18.0%) belonged to the ADT group, and 50 (82.0%) to the non-ADT group. Regarding the influence of ADT on the course of the disease, statistically significant differences were found neither in the death rate (27.3% vs. 34%; p = 0.481), nor in the presence of severe COVID-19: need for intubation or ICU admission (0% vs. 6.3%; p = 0.561) and need for corticoid treatment, interferon beta, or tocilizumab (60% vs. 34.7%; p = 0.128). Multivariate analysis adjusted for clinically relevant comorbidities did not find that ADT was a protective factor for worse clinical evolution (risk ratio [RR] 1.08; 95% confidence interval [CI], 0.64-1.83; p = 0.77) or death (RR, 0.67; 95% CI, 0.26-1.74; p = 0.41).

CONCLUSIONS

Our study confirms that COVID-19 is more severe in men. However, the use of ADT in patients with PC was not shown to prevent the risk of severe COVID-19.

Phytopharmaceuticals mediated Furin and TMPRSS2 receptor blocking: can it be a potential therapeutic option for Covid-19?

BACKGROUND

Currently, novel coronavirus disease (Covid-19) outbreak creates global panic across the continents, as people from almost all countries and territories have been affected by this highly contagious viral disease. The scenario is deteriorating due to lack of proper & specific target-oriented pharmacologically safe prophylactic agents or drugs, and or any effective vaccine. drug development is urgently required to back in the normalcy in the community and to combat this pandemic.

PURPOSE

Thus, we have proposed two novel drug targets, Furin and TMPRSS2, as Covid-19 treatment strategy. We have highlighted this target-oriented novel drug delivery strategy, based on their pathophysiological implication on SARS-CoV-2 infection, as evident from earlier SARS-CoV-1, MERS, and influenza virus infection via host cell entry, priming, fusion, and endocytosis. STUDY DESIGN &  METHODS: An earlier study suggested that Furin and TMPRSS2 knockout mice had reduced level of viral load and a lower degree of organ damage such as the lung. The present study thus highlights the promise of some selected novel and potential anti-viral Phytopharmaceutical that bind to Furin and TMPRSS2 as target.

RESULT

Few of them had shown promising anti-viral response in both preclinical and clinical study with acceptable therapeutic safety-index.

CONCLUSION

Hence, this strategy may limit life-threatening Covid-19 infection and its mortality rate through nano-suspension based intra-nasal or oral nebulizer spray, to treat mild to moderate SARS-COV-2 infection when Furin and TMPRSS2 receptor may initiate to express and activate for processing the virus to cause cellular infection by replication within the host cell and blocking of host-viral interaction.

The Dynamic Expression of Potential Mediators of Severe Acute Respiratory Syndrome Coronavirus 2 Cellular Entry in Fetal, Neonatal, and Adult Rhesus Monkeys

The coronavirus disease 2019 (COVID-19) pandemic, induced by the pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread rapidly all over the world. There is considerable variability among neonates, children, and adults in the incidence of infection and severe disease following exposure to SARS-CoV-2. In our study, we analyzed the transcriptome data of primate animal model of Rhesus monkeys to evaluate the expression levels of possible SARS-CoV-2 receptors and proteases and immunologic features in the lungs, colons, livers, and brains at different developmental stages. Our results revealed that ACE2 and TMPRSS2 were highly expressed in neonates compared with other populations, which imply the high incidence of infection. Other potential receptors and Type II transmembrane serine proteases (TTSPs) and cathepsin of endosomal proteases also exhibited dynamic and differential expression patterns. The expression of receptors (ACE2, BSG, and DPP4) and proteases (TMPRSS2, TMPRSS9, CTSL, and CTSB) were highly correlated during lung development, suggesting the high susceptibility of the lungs. TMPRSS9 was specifically highly expressed in the lungs and reached the highest level in neonates, similar to TMPRSS2. Moreover, the immune cell infiltration analysis revealed immunity immaturity in neonates, implying the association with the mild or moderate type of COVID-19. The results might help researchers design protective and therapeutic strategies for COVID-19 in populations at different ages.

Structural insights of key enzymes into therapeutic intervention against SARS-CoV-2

COVID-19 pandemic, caused by SARS-CoV-2, has drastically affected human health all over the world. After the emergence of the pandemic the major focus of efforts to attenuate the infection has been on repurposing the already approved drugs to treat COVID-19 adopting a fast-track strategy. However, to date a specific regimen to treat COVID-19 is not available. Over the last few months a substantial amount of data about the structures of various key proteins and their recognition partners involved in the SARS-CoV-2 pathogenesis has emerged. These studies have not only provided the molecular level descriptions ofthe viral pathogenesis but also laid the foundation for rational drug design and discovery. In this review, we have recapitulated the structural details of four key viral enzymes, RNA-dependent RNA polymerase, 3-chymotrypsin like protease, papain-like protease and helicase, and two host factors including angiotensin-converting enzyme 2 and transmembrane serine protease involved in the SARS-CoV-2 pathogenesis, and described the potential hotspots present on these structures which could be explored for therapeutic intervention. We have also discussed the significance of endoplasmic reticulum α-glucosidases as potential targets for anti-SARS-CoV-2 drug discovery.

Intrinsic disorder perspective of an interplay between the renin-angiotensin-aldosterone system and SARS-CoV-2

The novel severe acute respiratory syndrome (SARS) coronavirus SARS-CoV-2 walks the planet causing the rapid spread of the CoV disease 2019 (COVID-19) that has especially deleterious consequences for the patients with underlying cardiovascular diseases (CVDs). Entry of the SARS-CoV-2 into the host cell involves interaction of the virus (via the receptor-binding domain (RBD) of its spike glycoprotein) with the membrane-bound form of angiotensin-converting enzyme 2 (ACE2) followed by the virus-ACE2 complex internalization by the cell. Since ACE2 is expressed in various tissues, such as brain, gut, heart, kidney, and lung, and since these organs represent obvious targets for the SARS-CoV-2 infection, therapeutic approaches were developed to either inhibit ACE2 or reduce its expression as a means of prevention of the virus entry into the corresponding host cells. The problem here is that in addition to be a receptor for the SARS-CoV-2 entry into the host cells, ACE2 acts as a key component of the renin-angiotensin-aldosterone system (RAAS) aimed at the generation of a cascade of vasoactive peptides coordinating several physiological processes. In RAAS, ACE2 degrades angiotensin II, which is a multifunctional CVD-promoting peptide hormone and converts it to a heptapeptide angiotensin-(1-7) acting as the angiotensin II antagonist. As protein multifunctionality is commonly associated with the presence of flexible or disordered regions, we analyze here the intrinsic disorder predisposition of major players related to the SARS-CoV-2 - RAAS axis. We show that all considered proteins contain intrinsically disordered regions that might have specific functions. Since intrinsic disorder might play a role in the functionality of query proteins and be related to the COVID-19 pathogenesis, this work represents an important disorder-based outlook of an interplay between the renin-angiotensin-aldosterone system and SARS-CoV-2. It also suggests that consideration of the intrinsic disorder phenomenon should be added to the modern arsenal of means for drug development.

Inhibitors of type II transmembrane serine proteases in the treatment of diseases of the respiratory tract - A review of patent literature

INTRODUCTION

Type II transmembrane serine proteases (TTSPs) of the human respiratory tract generate high interest owing to their ability, among other roles, to cleave surface proteins of respiratory viruses. This step is critical in the viral invasion of coronaviruses, including SARS-CoV-2 responsible for COVID-19, but also influenza viruses and reoviruses. Accordingly, these cell surface enzymes constitute appealing therapeutic targets to develop host-based therapeutics against respiratory viral diseases. Additionally, their deregulated levels or activity has been described in non-viral diseases such as fibrosis, cancer, and osteoarthritis, making them potential targets in these indications.

AREAS COVERED

Areas covered: This review includes WIPO-listed patents reporting small molecules and peptide-based inhibitors of type II transmembrane serine proteases of the respiratory tract.

EXPERT OPINION

Expert opinion: Several TTSPs of the respiratory tract represent attractive pharmacological targets in the treatment of respiratory infectious diseases (notably COVID-19 and influenza), but also against idiopathic pulmonary fibrosis and lung cancer. The current emphasis is primarily on TMPRSS2, matriptase, and hepsin, yet other TTSPs await validation. Compounds listed herein are predominantly peptidomimetic inhibitors, some with covalent reversible mechanisms of action and high potencies. Their selectivity profile, however, are often only partially characterized. Preclinical data are promising and warrant further advancement in the above diseases.

SARS-CoV-2 Infection and Lung Cancer: Potential Therapeutic Modalities

Human coronaviruses, especially SARS-CoV-2, are emerging pandemic infectious diseases with high morbidity and mortality in certain group of patients. In general, SARS-CoV-2 causes symptoms ranging from the common cold to severe conditions accompanied by lung injury, acute respiratory distress syndrome in addition to other organs' destruction. The main impact upon SARS-CoV-2 infection is damage to alveolar and acute respiratory failure. Thus, lung cancer patients are identified as a particularly high-risk group for SARS-CoV-2 infection and its complications. On the other hand, it has been reported that SARS-CoV-2 spike (S) protein binds to angiotensin-converting enzyme 2 (ACE-2), that promotes cellular entry of this virus in concert with host proteases, principally transmembrane serine protease 2 (TMPRSS2). Today, there are no vaccines and/or effective drugs against the SARS-CoV-2 coronavirus. Thus, manipulation of key entry genes of this virus especially in lung cancer patients could be one of the best approaches to manage SARS-CoV-2 infection in this group of patients. We herein provide a comprehensive and up-to-date overview of the role of ACE-2 and TMPRSS2 genes, as key entry elements as well as therapeutic targets for SARS-CoV-2 infection, which can help to better understand the applications and capacities of various remedial approaches for infected individuals, especially those with lung cancer.

Androgen-deprivation therapies for prostate cancer and risk of infection by SARS-CoV-2: a population-based study (N = 4532)

Background

Cell entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) depends on binding of the viral spike (S) proteins to angiotensin-converting enzyme 2 and on S protein priming by TMPRSS2. Inhibition of TMPRSS2 may work to block or decrease the severity of SARS-CoV-2 infections. Intriguingly, TMPRSS2 is an androgen-regulated gene that is up-regulated in prostate cancer where it supports tumor progression and is involved in a frequent genetic translocation with the ERG gene. First- or second-generation androgen-deprivation therapies (ADTs) decrease the levels of TMPRSS2. Here we put forward the hypothesis that ADTs may protect patients affected by prostate cancer from SARS-CoV-2 infections.

Materials and methods

We extracted data regarding 9280 patients (4532 males) with laboratory-confirmed SARS-CoV-2 infection from 68 hospitals in Veneto, one of the Italian regions that was most affected by the coronavirus disease 2019 (COVID-19) pandemic. The parameters used for each COVID-19-positive patient were sex, hospitalization, admission to intensive care unit, death, tumor diagnosis, prostate cancer diagnosis, and ADT.

Results

There were evaluable 9280 SARS-CoV-2-positive patients in Veneto on 1 April 2020. Overall, males developed more severe complications, were more frequently hospitalized, and had a worse clinical outcome than females. Considering only the Veneto male population (2.4 million men), 0.2% and 0.3% of non-cancer and cancer patients, respectively, tested positive for SARS-CoV-2. Comparing the total number of SARS-CoV-2-positive cases, prostate cancer patients receiving ADT had a significantly lower risk of SARS-CoV-2 infection compared with patients who did not receive ADT (OR 4.05; 95% CI 1.55–10.59). A greater difference was found comparing prostate cancer patients receiving ADT with patients with any other type of cancer (OR 4.86; 95% CI 1.88–12.56).

Conclusion

Our data suggest that cancer patients have an increased risk of SARS-CoV-2 infections compared with non-cancer patients. However, prostate cancer patients receiving ADT appear to be partially protected from SARS-CoV-2 infections.

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SARS-CoV-2-infected men have a worse clinical outcome than women.

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Cancer patients have an increased risk of SARS-CoV-2 infection.

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Prostate cancer patients receiving androgen-deprivation therapies appear to be partially protected from the infection.

Membrane-anchored serine proteases as regulators of epithelial function

Cleavage of proteins in the extracellular milieu, including hormones, growth factors and their receptors, ion channels, and various cell adhesion and extracellular matrix molecules, plays a key role in the regulation of cell behavior. Among more than 500 proteolytic enzymes encoded by mammalian genomes, membrane-anchored serine proteases (MASPs), which are expressed on the surface of epithelial cells of all major organs, are excellently suited to mediate signal transduction across the epithelia and are increasingly being recognized as important regulators of epithelial development, function, and disease [ 1-3]. In this minireview, we summarize current knowledge of the in vivo roles of MASPs in acquisition and maintenance of some of the defining functions of epithelial tissues, such as barrier formation, ion transport, and sensory perception.

Novel antiviral drug discovery strategies to tackle drug-resistant mutants of influenza virus strains

INTRODUCTION

The emergence of drug-resistant influenza virus strains highlights the need for new antiviral therapeutics to combat future pandemic outbreaks as well as continuing seasonal cycles of influenza. Areas covered: This review summarizes the mechanisms of current FDA-approved anti-influenza drugs and patterns of resistance to those drugs. It also discusses potential novel targets for broad-spectrum antiviral drugs and recent progress in novel drug design to overcome drug resistance in influenza. Expert opinion: Using the available structural information about drug-binding pockets, research is currently underway to identify molecular interactions that can be exploited to generate new antiviral drugs. Despite continued efforts, antivirals targeting viral surface proteins like HA, NA, and M2, are all susceptible to developing resistance. Structural information on the internal viral polymerase complex (PB1, PB2, and PA) provides a new avenue for influenza drug discovery. Host factors, either at the initial step of viral infection or at the later step of nuclear trafficking of viral RNP complex, are being actively pursued to generate novel drugs with new modes of action, without resulting in drug resistance.

Matriptase-2: monitoring and inhibiting its proteolytic activity

Matriptase-2 (MT2) is a membrane-anchored proteolytic enzyme. It acts as the proteolytic key regulator in human iron homeostasis. A high expression level can lead to iron overload diseases, whereas mutations in the gene encoding MT2, TMPRSS6, may result in various forms of iron deficiency anemia. Recently, MT2 has been reported as a positive prognostic factor in breast and prostate cancers. However, the exact functions of MT2 in various pathophysiological conditions are still not fully understood. In this review, we describe the synthetic tools designed and synthesized to regulate or monitor MT2 proteolytic activity and present the latest knowledge about the role of MT2 in iron homeostasis and cancer.