Understanding the binding mechanism for potential inhibition of SARS-CoV-2 Mpro and exploring the modes of ACE2 inhibition by hydroxychloroquine.

As per the World Health Organization report, around 226 844 344 confirmed positive cases and 4 666 334 deaths are reported till September 17, 2021 due to the recent viral outbreak. A novel coronavirus (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) is responsible for the associated coronavirus disease (COVID-19), which causes serious or even fatal respiratory tract infection and yet no approved therapeutics or effective treatment is currently available to combat the outbreak. Due to the emergency, the drug repurposing approach is being explored for COVID-19. In this study, we attempt to understand the potential mechanism and also the effect of the approved antiviral drugs against the SARS-CoV-2 main protease (Mpro). To understand the mechanism of inhibition of the malaria drug hydroxychloroquine (HCQ) against SARS-CoV-2, we performed molecular interaction studies. The studies revealed that HCQ docked at the active site of the Human ACE2 receptor as a possible way of inhibition. Our in silico analysis revealed that the three drugs Lopinavir, Ritonavir, and Remdesivir showed interaction with the active site residues of Mpro. During molecular dynamics simulation, based on the binding free energy contributions, Lopinavir showed better results than Ritonavir and Remdesivir.

Investigating interactions between chloroquine/hydroxychloroquine and their single enantiomers and angiotensin-converting enzyme 2 by a cell membrane chromatography method.

Chloroquine and hydroxychloroquine have been studied since the early clinical treatment of SARS-CoV-2 outbreak. Considering these two chiral drugs are currently in use as the racemate, high-expression angiotensin-converting enzyme 2 cell membrane chromatography was established for investigating the differences of two paired enantiomers binding to angiotensin-converting enzyme 2 receptor. Molecular docking assay and detection of SARS-CoV-2 spike pseudotyped virus entry into angiotensin-converting enzyme 2-HEK293T cells were also conducted for further investigation. Results showed that each single enantiomer could bind well to angiotensin-converting enzyme 2, but there were differences between the paired enantiomers and corresponding racemate in frontal analysis. R-Chloroquine showed better angiotensin-converting enzyme 2 receptor binding ability compared to S-chloroquine/chloroquine (racemate). S-Hydroxychloroquine showed better angiotensin-converting enzyme 2 receptor binding ability than R-hydroxychloroquine/hydroxychloroquine. Moreover, each single enantiomer was proved effective compared with the control group; compared with S-chloroquine or the racemate, R-chloroquine showed better inhibitory effects at the same concentration. As for hydroxychloroquine, R-hydroxychloroquine showed better inhibitory effects than S-hydroxychloroquine, but it slightly worse than the racemate. In conclusion, R-chloroquine showed better angiotensin-converting enzyme 2 receptor binding ability and inhibitory effects compared to S-chloroquine/chloroquine (racemate). S-Hydroxychloroquine showed better angiotensin-converting enzyme 2 receptor binding ability than R-hydroxychloroquine/hydroxychloroquine (racemate), while the effect of preventing SARS-CoV-2 pseudovirus from entering cells was weaker than R-hydroxychloroquine/hydroxychloroquine (racemate).

Epigenetic targeting of the ACE2 and NRP1 viral receptors limits SARS-CoV-2 infectivity.

BACKGROUND: SARS-CoV-2 uses the angiotensin-converting enzyme 2 (ACE2) and neuropilin-1 (NRP1) receptors for entry into cells, and the serine protease TMPRSS2 for S protein priming. Inhibition of protease activity or the engagement with ACE2 and NRP1 receptors has been shown to be an effective strategy for blocking infectivity and viral spreading. Valproic acid (VPA; 2-propylpentanoic acid) is an epigenetic drug approved for clinical use. It produces potent antiviral and anti-inflammatory effects through its function as a histone deacetylase (HDAC) inhibitor. Here, we propose VPA as a potential candidate to tackle COVID-19, in which rapid viral spread and replication, and hyperinflammation are crucial elements. RESULTS: We used diverse cell lines (HK-2, Huh-7, HUVEC, Caco-2, and BEAS-2B) to analyze the effect of VPA and other HDAC inhibitors on the expression of the ACE-2 and NRP-1 receptors and their ability to inhibit infectivity, viral production, and the inflammatory response. Treatment with VPA significantly reduced expression of the ACE2 and NRP1 host proteins in all cell lines through a mechanism mediated by its HDAC inhibitory activity. The effect is maintained after SARS-CoV-2 infection. Consequently, the treatment of cells with VPA before infection impairs production of SARS-CoV-2 infectious viruses, but not that of other ACE2- and NRP1-independent viruses (VSV and HCoV-229E). Moreover, the addition of VPA 1 h post-infection with SARS-CoV-2 reduces the production of infectious viruses in a dose-dependent manner without significantly modifying the genomic and subgenomic messenger RNAs (gRNA and sg mRNAs) or protein levels of N protein. The production of inflammatory cytokines (TNF-α and IL-6) induced by TNF-α and SARS-CoV-2 infection is diminished in the presence of VPA. CONCLUSIONS: Our data showed that VPA blocks three essential processes determining the severity of COVID-19. It downregulates the expression of ACE2 and NRP1, reducing the infectivity of SARS-CoV-2; it decreases viral yields, probably because it affects virus budding or virions stability; and it dampens the triggered inflammatory response. Thus, administering VPA could be considered a safe treatment for COVID-19 patients until vaccines have been rolled out across the world.

Identification of potent human neutralizing antibodies against SARS-CoV-2 implications for development of therapeutics and prophylactics.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus that is spreading rapidly, which seriously impacts global public health and economy. Thus, developing effective drugs remains urgent. We identify two potent antibodies, nCoVmab1 and nCoVmab2, targeting the SARS-CoV-2 spike protein receptor-binding domain (RBD) with high affinities from a naïve human phage-displayed Fab library. nCoVmab1 and nCoVmab2 neutralize authentic SARS-CoV-2 with picomolar and nanomolar IC50 values, respectively. No detectable defects of nCoVmab1 and nCoVmab2 are found during the preliminary druggability evaluation. nCoVmab1 could reduce viral titer and lung injury when administered prophylactically and therapeutically in human angiotensin-converting enzyme II (hACE2)-transgenic mice. Therefore, phage display platform could be efficiently used for rapid development of neutralizing monoclonal antibodies (nmabs) with clinical potential against emerging infectious diseases. In addition, we determinate epitopes in RBD of these antibodies to elucidate the neutralizing mechanism. We also convert nCoVmab1 and nCoVmab2 to their germline formats for further analysis, which reveals the contribution of somatic hypermutation (SHM) during nCoVmab1 and nCoVmab2 maturation. Our findings not only provide two highly potent nmabs against SARS-CoV-2 as prophylactic and therapeutic candidates, but also give some clues for development of anti-SARS-CoV-2 agents (e.g., drugs and vaccines) targeting the RBD.

Human cell receptors: potential drug targets to combat COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the coronavirus disease 2019 (COVID-19). The World Health Organization (WHO) has announced that COVID-19 is a pandemic having a higher spread rate rather than the mortality. Identification of a potential approach or therapy against COVID-19 is still under consideration. Therefore, it is essential to have an insight into SARS-CoV-2, its interacting partner, and domains for an effective treatment. The present study is divided into three main categories, including SARS-CoV-2 prominent receptor and its expression levels, other interacting partners, and their binding domains. The first section focuses primarily on coronaviruses' general aspects (SARS-CoV-2, SARS-CoV, and the Middle East Respiratory Syndrome Coronaviruses (MERS-CoV)) their structures, similarities, and mode of infections. The second section discusses the host receptors which includes the human targets of coronaviruses like dipeptidyl peptidase 4 (DPP4), CD147, CD209L, Angiotensin-Converting Enzyme 2 (ACE2), and other miscellaneous targets (type-II transmembrane serine proteases (TTSPs), furin, trypsin, cathepsins, thermolysin, elastase, phosphatidylinositol 3-phosphate 5-kinase, two-pore segment channel, and epithelium sodium channel C-α subunit). The human cell receptor, ACE2 plays an essential role in the Renin-Angiotensin system (RAS) pathway and COVID-19. Thus, this section also discusses the ACE2 expression and risk of COVID-19 infectivity in various organs and tissues such as the liver, lungs, intestine, heart, and reproductive system in the human body. Absence of ACE2 protein expression in immune cells could be used for limiting the SARS-CoV-2 infection. The third section covers the current available approaches for COVID-19 treatment. Overall, this review focuses on the critical role of human cell receptors involved in coronavirus pathogenesis, which would likely be used in designing target-specific drugs to combat COVID-19.

Human parvovirus B19 interacts with globoside under acidic conditions as an essential step in endocytic trafficking.

The glycosphingolipid (GSL) globoside (Gb4) is essential for parvovirus B19 (B19V) infection. Historically considered the cellular receptor of B19V, the role of Gb4 and its interaction with B19V are controversial. In this study, we applied artificial viral particles, genetically modified cells, and specific competitors to address the interplay between the virus and the GSL. Our findings demonstrate that Gb4 is not involved in the binding or internalization process of the virus into permissive erythroid cells, a function that corresponds to the VP1u cognate receptor. However, Gb4 is essential at a post-internalization step before the delivery of the single-stranded viral DNA into the nucleus. In susceptible erythroid Gb4 knockout cells, incoming viruses were arrested in the endosomal compartment, showing no cytoplasmic spreading of capsids as observed in Gb4-expressing cells. Hemagglutination and binding assays revealed that pH acts as a switch to modulate the affinity between the virus and the GSL. Capsids interact with Gb4 exclusively under acidic conditions and dissociate at neutral pH. Inducing a specific Gb4-mediated attachment to permissive erythroid cells by acidification of the extracellular environment led to a non-infectious uptake of the virus, indicating that low pH-mediated binding to the GSL initiates active membrane processes resulting in vesicle formation. In summary, this study provides mechanistic insight into the interaction of B19V with Gb4. The strict pH-dependent binding to the ubiquitously expressed GSL prevents the redirection of the virus to nonpermissive tissues while promoting the interaction in acidic intracellular compartments as an essential step in infectious endocytic trafficking.

Antihypertensive Drugs and COVID-19 Risk: A Cohort Study of 2 Million Hypertensive Patients.

After initially hypothesizing a positive relationship between use of renin-angiotensin-aldosterone system inhibitors and risk of coronavirus disease 2019 (COVID-19), more recent evidence suggests negative associations. We examined whether COVID-19 risk differs according to antihypertensive drug class in patients treated by ACE (angiotensin-converting enzyme) inhibitors and angiotensin receptor blockers (ARBs) compared with calcium channel blockers (CCBs). Three exclusive cohorts of prevalent ACE inhibitors, ARB and CCB users, aged 18 to 80 years, from the French National Health Insurance databases were followed from February 15, 2020 to June 7, 2020. We excluded patients with a history of diabetes, known cardiovascular disease, chronic renal failure, or chronic respiratory disease during the previous 5 years, to only consider patients treated for uncomplicated hypertension and to limit indication bias. The primary end point was time to hospitalization for COVID-19. The secondary end point was time to intubation/death during a hospital stay for COVID-19. In a population of almost 2 million hypertensive patients (ACE inhibitors: 566 023; ARB: 958 227; CCB: 358 306) followed for 16 weeks, 2338 were hospitalized and 526 died or were intubated for COVID-19. ACE inhibitors and ARBs were associated with a lower risk of COVID-19 hospitalization compared with CCBs (hazard ratio, 0.74 [95% CI, 0.65-0.83] and 0.84 [0.76-0.93], respectively) and a lower risk of intubation/death. Risks were slightly lower for ACE inhibitor users than for ARB users. This large observational study may suggest a lower COVID-19 risk in hypertensive patients treated over a long period with ACE inhibitors or ARBs compared with CCBs. These results, if confirmed, tend to contradict previous hypotheses and raise new hypotheses.

Structural Basis of SARS-CoV-2- and SARS-CoV-Receptor Binding and Small-Molecule Blockers as Potential Therapeutics.

Over the past two decades, deadly coronaviruses, with the most recent being the severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) 2019 pandemic, have majorly challenged public health. The path for virus invasion into humans and other hosts is mediated by host-pathogen interactions, specifically virus-receptor binding. An in-depth understanding of the virus-receptor binding mechanism is a prerequisite for the discovery of vaccines, antibodies, and small-molecule inhibitors that can interrupt this interaction and prevent or cure infection. In this review, we discuss the viral entry mechanism, the known structural aspects of virus-receptor interactions (SARS-CoV-2 S/humanACE2, SARS-CoV S/humanACE2, and MERS-CoV S/humanDPP4), the key protein domains and amino acid residues involved in binding, and the small-molecule inhibitors and other drugs that have (as of June 2020) exhibited therapeutic potential. Specifically, we review the potential clinical utility of two transmembrane serine protease 2 (TMPRSS2)-targeting protease inhibitors, nafamostat mesylate and camostat mesylate, as well as two novel potent fusion inhibitors and the repurposed Ebola drug, remdesivir, which is specific to RNA-dependent RNA polymerase, against human coronaviruses, including SARS-CoV-2.

Step toward repurposing drug discovery for COVID-19 therapeutics through in silico approach.

The outbreak of SARS-CoV-2 has become a threat to global health and has led to a global economic crisis. Although the researchers worldwide are putting tremendous effort toward gaining more insights into this zoonotic virus and developing vaccines and therapeutic drugs, no vaccine or drug is yet available to combat COVID-19 effectively. Drug discovery is often a laborious, time-consuming, and expensive task. In this time of crisis, employing computational methods could provide a feasible alternative approach that can potentially be used for drug discovery. Therefore, a library of several antiparasitic and anti-inflammatory drugs was virtually screened against SARS-CoV-2 proteases to identify potential inhibitors. The identified inhibitory drugs were further analyzed to confirm their activities against SARS-CoV-2. Our results could prove to be helpful in repurposing the drug discovery approach, which could substantially reduce the expenses, time, and resources required.

Long-term trans-inhibition of the hepatitis B and D virus receptor NTCP by taurolithocholic acid.

Human hepatic bile acid transporter Na+/taurocholate cotransporting polypeptide (NTCP) represents the liver-specific entry receptor for the hepatitis B and D viruses (HBV/HDV). Chronic hepatitis B and D affect several million people worldwide, but treatment options are limited. Recently, HBV/HDV entry inhibitors targeting NTCP have emerged as promising novel drug candidates. Nevertheless, the exact molecular mechanism that NTCP uses to mediate virus binding and entry into hepatocytes is still not completely understood. It is already known that human NTCP mRNA expression is downregulated under cholestasis. Furthermore, incubation of rat hepatocytes with the secondary bile acid taurolithocholic acid (TLC) triggers internalization of the rat Ntcp protein from the plasma membrane. In the present study, the long-term inhibitory effect of TLC on transport function, HBV/HDV receptor function, and membrane expression of human NTCP were analyzed in HepG2 and human embryonic kidney (HEK293) cells stably overexpressing NTCP. Even after short-pulse preincubation, TLC had a significant long-lasting inhibitory effect on the transport function of NTCP, but the NTCP protein was still present at the plasma membrane. Furthermore, binding of the HBV/HDV myr-preS1 peptide and susceptibility for in vitro HDV infection were significantly reduced by TLC preincubation. We hypothesize that TLC rapidly accumulates in hepatocytes and mediates long-lasting trans-inhibition of the transport and receptor function of NTCP via a particular TLC-binding site at an intracellularly accessible domain of NTCP. Physiologically, this trans-inhibition might protect hepatocytes from toxic overload of bile acids. Pharmacologically, it provides an interesting novel NTCP target site for potential long-acting HBV/HDV entry inhibitors.NEW & NOTEWORTHY The hepatic bile acid transporter NTCP is a high-affinity receptor for hepatitis B and D viruses. This study shows that TLC rapidly accumulates in NTCP-expressing hepatoma cells and mediates long-lasting trans-inhibition of NTCP's transporter and receptor function via an intracellularly accessible domain, without substantially affecting its membrane expression. This domain is a promising novel NTCP target site for pharmacological long-acting HBV/HDV entry inhibitors.

Nasal lavage containing Angiotensin-Converting Enzyme-2 agonist can prevent and reduce viral load in COVID-19.

COVID-19 has been the talk of the year 2020, taking many lives and leaving others in critical conditions. It has clearly and severally been reported that the SARSCoV-2 uses the Angiotensin Converting Enzyme-2 receptors to penetrate and infect cells. Reports have also stated that the nasal and olfactory mucosa are overloaded with these receptors. We emphasize that anosmia in COVID-19 is secondary to the binding of the SARSCoV-2 to Angiotensin Converting Enzyme-2 receptors on the olfactory mucosa. A hypotheses pertaining to the presentation, diagnosis, management and possible prevention of SARS-CoV-2 is proposed. Given the high false negative rates of the polymerase chain reaction (PCR) tests, we suggest that COVID-19 negative patients with anosmia without any other nasal symptom should raise a high index of suspicion and should be further evaluated. We propose the formulation and use of Angiotensin Converting Enzyme-2 receptors agonist or angiotensin receptor blockers (ARBs) as nasal lavage, to reduce the viral load of confirmed positive patients, and as a mode of prevention, especially in high risk patients, until a vaccine is developed. These medications are readily available and testing this theory involves determination of the correct dosage of angiotensin receptor blockers or ACE inhibitors (via dilution in water) that can be used as nasal lavage and performing efficacy trials. Potential side effects to be monitored for include low blood pressure or changes in heart rate. Administration of a medicated nasal lavage may be easier and rapidly disseminated on the nasal mucosa.

On the whereabouts of SARS-CoV-2 in the human body: A systematic review.

Since SARS-CoV-2 appeared in the human population, the scientific community has scrambled to gather as much information as possible to find good strategies for the containment and treatment of this pandemic virus. Here, we performed a systematic review of the current (pre)published SARS-CoV-2 literature with a focus on the evidence concerning SARS-CoV-2 distribution in human tissues and viral shedding in body fluids. In addition, this evidence is aligned with published ACE2 entry-receptor (single cell) expression data across the human body to construct a viral distribution and ACE2 receptor body map. We highlight the broad organotropism of SARS-CoV-2, as many studies identified viral components (RNA, proteins) in multiple organs, including the pharynx, trachea, lungs, blood, heart, vessels, intestines, brain, male genitals and kidneys. This also implicates the presence of viral components in various body fluids such as mucus, saliva, urine, cerebrospinal fluid, semen and breast milk. The main SARS-CoV-2 entry receptor, ACE2, is expressed at different levels in multiple tissues throughout the human body, but its expression levels do not always correspond with SARS-CoV-2 detection, indicating that there is a complex interplay between virus and host. Together, these data shed new light on the current view of SARS-CoV-2 pathogenesis and lay the foundation for better diagnosis and treatment of COVID-19 patients.

Scaffold morphing of arbidol (umifenovir) in search of multi-targeting therapy halting the interaction of SARS-CoV-2 with ACE2 and other proteases involved in COVID-19.

The rapid emergence of novel coronavirus, SARS-coronavirus 2 (SARS-CoV-2), originated from Wuhan, China, imposed a global health emergency. Angiotensin-converting enzyme 2 (ACE2) receptor serves as an entry point for this deadly virus while the proteases like furin, transmembrane protease serine 2 (TMPRSS2) and 3 chymotrypsin-like protease (3CLpro) are involved in the further processing and replication of SARS-CoV-2. The interaction of SP with ACE2 and these proteases results in the SARS-CoV-2 invasion and fast epidemic spread. The small molecular inhibitors are reported to limit the interaction of SP with ACE2 and other proteases. Arbidol, a membrane fusion inhibitor approved for influenza virus is currently undergoing clinical trials against COVID-19. In this context, we report some analogues of arbidol designed by scaffold morphing and structure-based designing approaches with a superior therapeutic profile. The representative compounds A_BR4, A_BR9, A_BR18, A_BR22 and A_BR28 restricted the interaction of SARS-CoV-2 SP with ACE2 and host proteases furin and TMPRSS2. For 3CLPro, Compounds A_BR5, A_BR6, A_BR9 and A_BR18 exhibited high binding affinity, docking score and key residue interactions. Overall, A_BR18 and A_BR28 demonstrated multi-targeting potential against all the targets. Among these top-scoring molecules A_BR9, A_BR18, A_BR22 and A_BR28 were predicted to confer favorable ADME properties.

Spironolactone may provide protection from SARS-CoV-2: Targeting androgens, angiotensin converting enzyme 2 (ACE2), and renin-angiotensin-aldosterone system (RAAS).

In coronavirus disease-19 (COVID-19), four major factors have been correlated with worse prognosis: aging, hypertension, obesity, and exposure to androgen hormones. Angiotensin-converting enzyme-2 (ACE2) receptor, regulation of the renin-angiotensin-aldosterone system (RAAS), and transmembrane serine protease 2 (TMPRSS2) action are critical for the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) cell entry and infectivity. ACE2 expression and RAAS are abnormal in hypertension and obesity, while TMPRSS2 is overexpressed when exposed to androgens, which may justify why these factors are overrepresented in COVID-19. Among therapeutic targets for SARS-CoV-2, we hypothesized that spironolactone, a long used and safe mineralocorticoid and androgen receptors antagonist, with effective anti-hypertensive, cardioprotective, nephroprotective, and anti-androgenic properties may offer pleiotropic actions in different sites to protect from COVID-19. Current data shows that spironolactone may concurrently mitigate abnormal ACE2 expression, correct the balances membrane-attached and free circulating ACE2 and between angiotensin II and Angiotensin-(1-7) (Ang-(1-7)), suppress androgen-mediated TMPRSS2 activity, and inhibit obesity-related RAAS dysfunctions, with consequent decrease of viral priming. Hence, spironolactone may provide protection from SARS-CoV-2, and has sufficient plausibility to be clinically tested, particularly in the early stages of COVID-19.

The war against the SARS-CoV2 infection: Is it better to fight or mitigate it?

In trying to understand the biochemical mechanism involved in the recent pandemic COVID-19, there is currently growing interest in angiotensin-converting enzyme II (ACE2). Nevertheless, the attempts to counteract COVID-19 interference with this enzymatic cascade are frustrating, and the results have thus far been inconclusive. Let's start again by considering the involved factors in an alternative way: we could postulate that COVID-19 could be more aggressive/fatal due to a high level of "basal" inflammation with low Nitric Oxide (NO) levels in hypertensive, diabetic and obese patients. Interestingly, the "protective" effects of several factors (such as estrogens) may play a role by increasing the formation of endogenous NO. From a therapeutic point of view, phosphodiesterase type 5 inhibitors such as oral Tadalafil, could be used in order to increase the basal NO levels. In this way, we don't fight the virus, but we may be able to mitigate its effects.

Coronaviruses and Integrin αvß3: Does Thyroid Hormone Modify the Relationship?

BACKGROUND: Uptake of coronaviruses by target cells involves binding of the virus by cell ectoenzymes. For the etiologic agent of COVID-19 (SARS-CoV-2), a receptor has been identified as angiotensin-converting enzyme-2 (ACE2). Recently it has been suggested that plasma membrane integrins may be involved in the internalization and replication of clinically important coronaviruses. For example, integrin αvß3 is involved in the cell uptake of a model porcine enteric α-coronavirus that causes human epidemics. ACE2 modulates the intracellular signaling generated by integrins. OBJECTIVE: We propose that the cellular internalization of αvß3 applies to uptake of coronaviruses bound to the integrin, and we evaluate the possibility that clinical host T4 may contribute to target cell uptake of coronavirus and to the consequence of cell uptake of the virus. DISCUSSION AND CONCLUSIONS: The viral binding domain of the integrin is near the Arg-Gly-Asp (RGD) peptide-binding site and RGD molecules can affect virus binding. In this same locale on integrin αvß3 is the receptor for thyroid hormone analogues, particularly, L-thyroxine (T4). By binding to the integrin, T4 has been shown to modulate the affinity of the integrin for other proteins, to control internalization of αvß3 and to regulate the expression of a panel of cytokine genes, some of which are components of the 'cytokine storm' of viral infections. If T4 does influence coronavirus uptake by target cells, other thyroid hormone analogues, such as deaminated T4 and deaminated 3,5,3'-triiodo-L-thyronine (T3), are candidate agents to block the virus-relevant actions of T4 at integrin αvß3 and possibly restrict virus uptake.

Sex differences in SARS-CoV-2 infection rates and the potential link to prostate cancer.

The recent outbreak of infections and the pandemic caused by SARS-CoV-2 represent one of the most severe threats to human health in more than a century. Emerging data from the United States and elsewhere suggest that the disease is more severe in men. Knowledge gained, and lessons learned, from studies of the biological interactions and molecular links that may explain the reasons for the greater severity of disease in men, and specifically in the age group at risk for prostate cancer, will lead to better management of COVID-19 in prostate cancer patients. Such information will be indispensable in the current and post-pandemic scenarios.

[The RAAS and SARS-CoV-2: A riddle to solve]. / El SRAA y el SARS-CoV-2: el acertijo a resolver.

The first case of COVID-19 was reported on 31 December 2019 in Wuhan, China. Ever since there has been unprecedented and growing interest in learning about all aspects of this new disease. Debate has been generated as to the association between antihypertensive therapy with renin-angiotensin-aldosterone system (RAAS) inhibitors and SARS-CoV-2 infection. While many questions as yet remain unanswered, the aim of this report is to inform health professionals about the current state of knowledge. Because this is an ever-evolving topic, the recommendation is that it be updated as new evidence becomes available. Below, we provide a review of pre-clinical and clinical studies that link coronavirus to the RAAS.

Role of Interleukin-6 in Lung Complications in Patients With COVID-19: Therapeutic Implications.

COVID-19 is viral respiratory infection with frequently fatal lung complications in the elderly or in people with serious comorbidities. Lung destruction appears to be associated with a cytokine storm related to an increased level of interleukin-6 (IL6). Therapeutic targeting of the interleukin-6 signaling pathway can attenuate such a cytokine storm and can be beneficial for patients with COVID-19 in danger of pulmonary failure. This article demonstrates the importance of IL6 in progression of disease and the possibility of inhibition of IL6 signaling in COVID-19 therapy.