MERS-CoV Infection Research Articles

In vitro study on efficacy of PHELA, an African traditional drug against SARS-CoV-2

In 2019, coronavirus has made the third apparition in the form of SARS-CoV-2, a novel strain of coronavirus that is extremely pathogenic and it uses the same receptor as SARS-CoV, the angiotensin-converting enzyme 2 (ACE2). However, more than 182 vaccine candidates have been announced; and 12 vaccines have been approved for use, although, even vaccinated individuals are still vulnerable to infection. In this study, we investigated PHELA, recognized as an herbal combination of four exotic African medicinal plants namely; Clerodendrum glabrum E. Mey. Lamiaceae, Gladiolus dalenii van Geel, Rotheca myricoides (Hochst.) Steane & Mabb, and Senna occidentalis (L.) Link; as a candidate therapy for COVID-19. In vitro testing found that PHELA inhibited > 90% of SARS-CoV-2 and SARS-CoV infection at concentration levels of 0.005 mg/ml to 0.03 mg/ml and close to 100% of MERS-CoV infection at 0.1 mg/ml to 0.6 mg/ml. The in vitro average IC50 of PHELA on SARS-COV-2, SARS-CoV and MERS-COV were ~ 0.01 mg/ml. Secondly in silico docking studies of compounds identified in PHELA showed very strong binding energy interactions with the SARS-COV-2 proteins. Compound 5 showed the highest affinity for SARS-COV-2 protein compared to other compounds with the binding energy of − 6.8 kcal mol−1. Our data showed that PHELA has potential and could be developed as a COVID-19 therapeutic.

Encapsulation of MERS antigen into α-GalCer-bearing-liposomes elicits stronger effector and memory immune responses in immunocompetent and leukopenic mice

ObjectivesHere, we prepared a liposome-based vaccine formulation containing Middle East Respiratory Syndrome Coronavirus papain-like protease (MERS-CoV-PLpro). MethodsA persistent leukopenic condition was induced in mice by injecting cyclophosphamide (CYP) three days before each dose of immunization. Mice were immunized on days 0, 14 and 21 with α-GalCer-bearing MERS-CoV PLpro-encapsulated DPPC-liposomes (α-GalCer-MERS-PLpro-liposomes or MERS-CoV PLpo-encapsulated DPPC-liposomes (MERS-PLpro-liposomes), whereas the antigen emulsified in Alum (MERS-PLpro-Alum) was taken as a control. On day 26, the blood was taken from the immunized mice to analyze IgG titer, whereas the splenocytes were used to analyze the lymphocyte proliferation and the level of cytokines. In order to assess the memory immune response, mice were given a booster dose after 150 days of the last immunization. ResultsThe higher levels of MERS-CoV-PLpro-specific antibody titer, IgG2a and lymphocyte proliferation were noticed in mice immunized with α-GalCer-MERS-PLpro-liposomes. Besides, the splenocytes from mice immunized with α-GalCer-MERS-PLpro-liposomes produced larger amounts of IFN-γ as compared to the splenocytes from MERS-PLpro-liposomes or MERS- PLpro-Alum immunized mice. Importantly, an efficient antigen-specific memory immune response was observed in α-GalCer-MERS-PLpro-liposomes immunized mice. ConclusionsThese findings suggest that α-GalCer-MERS-PLpro-liposomes may substantiate to be a successful vaccine formulation against MERS-CoV infection, particularly in immunocompromised individuals.

Effective Interferon Lambda Treatment Regimen To Control Lethal MERS-CoV Infection in Mice.

Effective broad-spectrum antivirals are critical to prevent and control emerging human coronavirus (hCoV) infections. Despite considerable progress made toward identifying and evaluating several synthetic broad-spectrum antivirals against hCoV infections, a narrow therapeutic window has limited their success. Enhancing the endogenous interferon (IFN) and IFN-stimulated gene (ISG) response is another antiviral strategy that has been known for decades. However, the side effects of pegylated type-I IFNs (IFN-Is) and the proinflammatory response detected after delayed IFN-I therapy have discouraged their clinical use. In contrast to IFN-Is, IFN-λ, a dominant IFN at the epithelial surface, has been shown to be less proinflammatory. Consequently, we evaluated the prophylactic and therapeutic efficacy of IFN-λ in hCoV-infected airway epithelial cells and mice. Human primary airway epithelial cells treated with a single dose of IFN-I (IFN-α) and IFN-λ showed similar ISG expression, whereas cells treated with two doses of IFN-λ expressed elevated levels of ISG compared to that of IFN-α-treated cells. Similarly, mice treated with two doses of IFN-λ were better protected than mice that received a single dose, and a combination of prophylactic and delayed therapeutic regimens completely protected mice from a lethal Middle East respiratory syndrome CoV (MERS-CoV) infection. A two-dose IFN-λ regimen significantly reduced lung viral titers and inflammatory cytokine levels with marked improvement in lung inflammation. Collectively, we identified an effective regimen for IFN-λ use and demonstrated the protective efficacy of IFN-λ in MERS-CoV-infected mice. IMPORTANCE Effective antiviral agents are urgently required to prevent and treat individuals infected with SARS-CoV-2 and other emerging viral infections. The COVID-19 pandemic has catapulted our efforts to identify, develop, and evaluate several antiviral agents. However, a narrow therapeutic window has limited the protective efficacy of several broad-spectrum and CoV-specific antivirals. IFN-λ is an antiviral agent of interest due to its ability to induce a robust endogenous antiviral state and low levels of inflammation. Here, we evaluated the protective efficacy and effective treatment regimen of IFN-λ in mice infected with a lethal dose of MERS-CoV. We show that while prophylactic and early therapeutic IFN-λ administration is protective, delayed treatment is detrimental. Notably, a combination of prophylactic and delayed therapeutic administration of IFN-λ protected mice from severe MERS. Our results highlight the prophylactic and therapeutic use of IFN-λ against lethal hCoV and likely other viral lung infections.

Application of M-cell targeting ligand Co4B enhances Ag-specific mucosal and systemic immunity and protection against MERS-CoV infection after intranasal immunization

Abstract Middle East respiratory syndrome is associated with severe pneumonia and poses a global public health threat. Authorized vaccines against the causative agent of MERS-CoV are urgently needed. In order to optimize the efficacy of recombinant vaccines, adjuvants should be required. Therefore, we previously identified a ligand Co4B as an adjuvant to enhance Ag delivery to the nasal mucosa immune compartment and promote Ag-specific mucosal and systemic immune responses via intranasal administration against A. pleuropneumoniae infection in a murine model. Based on the pathogenesis of MERS-CoV which infects host following respiratory route; thus, we generated a recombinant protein conjugated with Co4B to the MERS-CoV spike protein receptor-binding domain (S-RBD) to develop mucosal subunit vaccine candidate. Ag-specific mucosal IgA and systemic IgG antibody responses, together with virus-neutralizing capacities, were highly elicited in C57BL/6 and human dipeptidyl peptidase 4-transgenic (hDPP4-Tg) mice intranasally immunized with Co4B-conjugated S-RBD compared to those immunized with originally S-RBD. Ag-specific T cell-mediated immunity was also induced in the spleen and lungs of mice intranasally immunized with Co4B-conjugated S-RBD. Intranasal immunization of hDPP4-Tg mice with Co4B-conjugated S-RBD prominently reduced immune cell infiltration into the tissues of virus-challenged mice. Finally, Co4B-conjugated S-RBD-immunized mice demonstrated were improved protection against infection, more likely to survive, and exhibited less body weight loss. Collectively, our results suggest that Co4B-conjugated S-RBD could be used as an improved subunit vaccine candidate against MERS-CoV infection. This work was supported by the Ministry of Science and ICT No. 2020K1A4A7A02095058 and the NRF funded by the Ministry of Education No. 2019R1I1A3A01062224. Ms. Y. L. Yang and Ms. B.-H. Cho were supported by the BK21 FOUR program of the Department of Bioactive Material Sciences.

Delivery of MERS antigen encapsulated in α-GalCer-bearing liposomes elicits stronger antigen-specific immune responses

Alpha-Galactosylceramide (α-GalCer) effectively activates the natural killer T (NKT) cells to secrete remarkable amounts of Th1 and Th2 cytokines and therefore, acts as a potential immunoadjuvant in vaccine formulation. In the present study, we prepared α-GalCer-bearing or α-GalCer-free liposomes and loaded them with Middle East Respiratory Syndrome Coronavirus papain-like protease (α-GalCer-Lip-MERS-CoV PLpro or Lip-MERS-CoV PLpro). These formulations were injected in mice to investigate the antigen-specific humoral and cell-mediated immune responses. The immunisation with α-GalCer-Lip-MERS-CoV PLpro or Lip-MERS-CoV PLpro did not induce any notable toxicity in immunised mice. The results demonstrated that mice immunised with α-GalCer-Lip-MERS-CoV PLpro showed greater antigen-specific antibody titre, switching of IgG isotyping to IgG2a subclass and higher lymphocyte proliferation. Moreover, the splenocytes from α-GalCer-Lip-MERS-CoV PLpro immunised mice secreted greater levels of IFN-γ, IL-4, IL-2 and IL-12. Interestingly, a booster dose induced stronger memory immune responses in mice previously immunised with α-GalCer-Lip-MERS-CoV PLpro. In summary, α-GalCer-Lip-MERS-CoV PLpro may prove to be a promising vaccine formulation to protect the individuals against MERS-CoV infection.

Anticoronaviral Activity of the Natural Phloroglucinols, Dryocrassin ABBA and Filixic Acid ABA from the Rhizome of Dryopteris crassirhizoma by Targeting the Main Protease of SARS-CoV-2.

The rhizome of Dryopteris crassirhizoma Nakai. (Dryopteridaceae) has been used in traditional medicine in East Asia and has recently been reported to have anticancer, anti-inflammation, and antibacterial activity as well as antiviral activity. Natural phloroglucinols from D. crassirhizoma, dryocrassin ABBA and filixic acid ABA were reported to inhibit influenza virus infection with an inhibitory activity on neuraminidase. In this study, we found that dryocrassin ABBA and filixic acid ABA have an inhibitory activity against the main protease of SARS-CoV-2. Therefore, dryocrassin ABBA and filixic acid ABA exhibited inhibitory activity against SARS-CoV-2 infection in Vero cells dose-dependently using the immunofluorescence-based antiviral assays. Moreover, these compounds inhibited SARS-CoV and MERS-CoV infection, suggesting their broad-spectrum anticoronaviral activity. In addition, a 5-day repeated-dose toxicity study of dryocrassin ABBA and filixic acid ABA suggested that an approximately lethal dose of these compounds in mice was >10 mg/kg. Pharmacokinetic studies of dryocrassin ABBA showed good microsomal stability, low hERG inhibition, and low CYP450 inhibition. In vivo pharmacokinetic properties of dryocrassin ABBA showed a long half-life (5.5–12.6 h) and high plasma exposure (AUC 19.3–65 μg·h/mL). Therefore, dryocrassin ABBA has therapeutic potential against emerging coronavirus infections, including COVID-19.

Proteomic landscape of SARS-CoV-2- and MERS-CoV-infected primary human renal epithelial cells.

Acute kidney injury is associated with mortality in COVID-19 patients. However, host cell changes underlying infection of renal cells with SARS-CoV-2 remain unknown and prevent understanding of the molecular mechanisms that may contribute to renal pathology. Here, we carried out quantitative translatome and whole-cell proteomics analyses of primary renal proximal and distal tubular epithelial cells derived from human donors infected with SARS-CoV-2 or MERS-CoV to disseminate virus and cell type-specific changes over time. Our findings revealed shared pathways modified upon infection with both viruses, as well as SARS-CoV-2-specific host cell modulation driving key changes in innate immune activation and cellular protein quality control. Notably, MERS-CoV infection-induced specific changes in mitochondrial biology that were not observed in response to SARS-CoV-2 infection. Furthermore, we identified extensive modulation in pathways associated with kidney failure that changed in a virus- and cell type-specific manner. In summary, we provide an overview of the effects of SARS-CoV-2 or MERS-CoV infection on primary renal epithelial cells revealing key pathways that may be essential for viral replication.

Pathophysiology of Covid-19

In late 2019, in late December, a virus now called SARS-CoV-2 caused unusual respiratory illnesses in Wuhan, Hubei Province, China. The disease was called COVID-19. The virus is contagious to humans and has caused a worldwide outbreak. Acute kidney disease (AKI) is found in 5 to 15% of cases of SARS-CoV and MERS-CoV infection, and according to recorded statistics, the mortality rate is approximately higher. 60 to 90%. Controversial data on the adverse effects of PPI and COVID-19, which were positively evaluated with famotidine under pharmacological observations for GI treatments in COVID-19 patients. Severe myocardial injury, as Increased levels of cardiac biomarkers or electrocardiogram abnormalities were detectable in 7 to 20% of patients with Covid 19 in the first studies in China. Keywords: Covid-19; Effect of Covid-19; Heart Covid-19; Pathophysiology Covid-19

Possible Mechanisms of Drugs Used in the Treatment of COVID-19: A Pharmacological Perspective

Coronaviruses are a type of virus that can infect both animals and humans. Coronaviruses are divided into thirty-nine species and twenty-seven subgenus in the family Coronaviridae, according to the current classification. Seven of these are known to induce respiratory infections, while four others can cause cold-like symptoms on a regular basis. SARS CoV, MERS-CoV, and SARS CoV-2 infection are three examples of viral rebound. They are to blame for SARS, MERS, and the most recent Coronavirus epidemic discovered in 2019. (COVID-19). The World Health Organization declared the respiratory sickness caused by the SARS-CoV-2 infection to be a pandemic (WHO). For this COVID-19, there are currently no properly shown managements. The virology of SARS-CoV-2 has yielded a large number of therapeutic targets. Remdesivir appears to be the most promising treatment. Currently, COVID-19 is treated with Dexamethasone, Tocilizumab, Remdesivir, Chloroquine and Hydroxychloroquine, Lopinavir, Favipiravir, Niclosamide, Azithromycin, Sarilumab, Baricitinib, Ruxolitinib, Ribavarin, Nitazoxanide, Umifenovir, Camostat, Ciclesonide, Darun They exert their effects through blocking receptors such as IL 6, TMPRSS2, CD147, and AAKI, as well as RNA dependent RNA polymerase, membrane fusion, endocytosis, and proteolysis. The authors of this study looked at the available literature on the SARS-CoV-2 virus and the COVID-19 virus in terms of therapeutic evidence. This in-depth and thorough examination provides an excellent overview of the most up-to-date information on the medications used to treat COVID-19.

Liposome-Mediated Delivery of MERS Antigen Induces Potent Humoral and Cell-Mediated Immune Response in Mice.

The advancements in the field of nanotechnology have provided a great platform for the development of effective antiviral vaccines. Liposome-mediated delivery of antigens has been shown to induce the antigen-specific stimulation of the humoral and cell-mediated immune responses. Here, we prepared dried, reconstituted vesicles (DRVs) from DPPC liposomes and used them as the vaccine carrier system for the Middle East respiratory syndrome coronavirus papain-like protease (DRVs-MERS-CoV PLpro). MERS-CoV PLpro emulsified in the Incomplete Freund’s Adjuvant (IFA-MERS-CoV PLpro) was used as a control. Immunization of mice with DRVs-MERS-CoV PLpro did not induce any notable toxicity, as revealed by the levels of the serum alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) in the blood of immunized mice. Immunization with DRVs-MERS-CoV PLpro induced greater antigen-specific antibody titer and switching of IgG1 isotyping to IgG2a as compared to immunization with IFA-MERS-CoV PLpro. Moreover, splenocytes from mice immunized with DRVs-MERS-CoV PLpro exhibited greater proliferation in response to antigen stimulation. Moreover, splenocytes from DRVs-MERS-CoV PLpro-immunized mice secreted significantly higher IFN-γ as compared to splenocytes from IFA-MERS-CoV PLpro mice. In summary, DRVs-MERS-CoV PLpro may prove to be an effective prophylactic formulation to prevent MERS-CoV infection.

Duration of MERS – Coronavirus Antibodies in a Small Closed Dromedary Camel Herd in Dubai

This investigation shows that MERS-CoV ELISA antibodies remain in dromedary camels at least for 9 years, most probably lifelong. The viral infection was most likely acquired at a young age when maternal antibodies have receded between 4 to 8 month of age. Additionally, in the investigated herd, the 4 ELISA antibody negative dromedary camels remained negative also for 9 years, indicating, that no MERS-CoV was circulating in the herd. Until today, the specific source of MERS-CoV infection for young dromedaries remains unknown.

Periodic oscillation for a class of in-host MERS-CoV infection model with CTL immune response.

The purpose of this paper is to give some sufficient conditions for the existence of periodic oscillation of a class of in-host MERS-Cov infection model with cytotoxic T lymphocyte (CTL) immune response. A new technique is developed to obtain a lower bound of the state variable characterizing CTL immune response in the model. Our results expand on some previous works.

Cross-sectional study of Middle East respiratory syndrome coronavirus in humans and dromedary camels in Diyala, Iraq.

Middle East respiratory syndrome (MERS) is a zoonotic viral disease transmitted from dromedaries to humans. To date, more than 1500 cases of MERS have been reported and 80% of all cases have occurred in the Kingdom of Saudi Arabia (KSA). This cross-sectional study was carried out to figure out the rate of infection among humans and dromedary camels and to explore the risk factors. This study was conducted in Diyala Province, Iraq for the period from August 2017 to October 2018. Human subjects included 90 participants; 34 (37.8%) were females and 56 (62.2%) were males. Additionally, 90 dromedary camels were also included, 50 (55.6%) males and 40 (44.4%) females. Serum samples from subjects were collected and tested for the presence of anti-MERS-coronavirus (CoV) immunoglobulin g (IgG). The results revealed that 46 (51.1%) of human subjects were positive for anti-MERS-CoV IgG, (95% confidence interval (CI) for the prevalence rate 40.9-61.3) with a mean titer of anti-MERS-CoV IgG antibodies (Ab) of 81.2 U/mL. The anti-MERS-CoV IgG positivity rate was insignificantly higher, but the mean of anti-MERS-CoV IgG titer was significantly higher among females (p = 0.12 and p < 0.004, respectively). Furthermore, the anti-MERS-CoV IgG positivity rate and Ab titer were significantly higher among those people who visited KSA for Hajj or Umrah (p < 0.001 and p < 0.001, respectively). In camels, 81 (90.0%) were positive for anti-MERS-CoV IgG, (95% CI for the prevalence rate 82.5-94.9), with a mean titer of 99.8 U/mL. The MERS-CoV infection rate was high among both Iraqi humans and dromedary camels. Further confirmatory studies are needed, and setting up of national precaution program is essential.

Molecular mechanisms for understanding the association between TMPRSS2 and beta coronaviruses SARS-CoV-2, SARS-CoV and MERS-CoV infection: scoping review.

The aim of this scoping review was to identify knowledge gaps and to describe the current state of the research on the association between TMPRSS2 and the essential beta coronaviruses (Beta-CoVs) infection and the molecular mechanisms for this association. We searched MEDLINE (OVID), EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL). We included 13 studies. Evidence shows an essential role of TMPRSS2 in Spike protein activation, entry, and spread into host cells. Co-expression of TMPRSS2 with cell surface receptors (ACE2 or DPP4) increased virus entry. This serine protease is involved in the formation of large syncytia between infected cells. TMPRSS2 cleaved the Spike protein of SARS-CoV, SARS-CoV-2, and MERS-CoV, and increased virus propagation. Accumulating evidence suggests that TMPRSS2 is an essential protease for virus replication. We highlighted its critical molecular role in membrane fusion and the impact in viral mRNA replication, then promoting/driving pathogenesis and resistance.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00203-021-02727-3.

Broad Spectrum Antiviral Properties of Cardiotonic Steroids Used as Potential Therapeutics for Emerging Coronavirus Infections.

Cardiotonic steroids are steroid-like natural compounds known to inhibit Na+/K+-ATPase pumps. To develop a broad-spectrum antiviral drug against the emerging coronavirus infection, this study assessed the antiviral properties of these compounds. The activity of seven types of cardiotonic steroids against the MERS-CoV, SARS-CoV, and SARS-CoV-2 coronavirus varieties was analyzed using immunofluorescence antiviral assay in virus-infected cells. Bufalin, cinobufagin, and telocinobufagin showed high anti-MERS-CoV activities (IC50, 0.017~0.027 μM); bufalin showed the most potent anti-SARS-CoV and SARS-CoV-2 activity (IC50, 0.016~0.019 μM); cinobufotalin and resibufogenin showed comparatively low anti-coronavirus activity (IC50, 0.231~1.612 μM). Differentially expressed genes in Calu3 cells treated with cinobufagin, telocinobufagin, or bufalin, which had high antiviral activity during MERS-CoV infection were analyzed using QuantSeq 3′ mRNA-Seq analysis and data showed similar gene expression patterns. Furthermore, the intraperitoneal administration of 10 mg/kg/day bufalin, cinobufagin, or digitoxin induced 100% death after 1, 2, and 4 days in 5-day repeated dose toxicity studies and it indicated that bufalin had the strongest toxicity. Pharmacokinetic studies suggested that telocinobufagin, which had high anti-coronavirus activity and low toxicity, had better microsomal stability, lower CYP inhibition, and better oral bioavailability than cinobufagin. Therefore, telocinobufagin might be the most promising cardiotonic steroid as a therapeutic for emerging coronavirus infections, including COVID-19.

COVID-19 Infection and Neuropathological Features.

The pathology associated with COVID-19 infection is progressively being revealed. Recent postmortem assessments have revealed acute airway inflammation as well as diffuse alveolar damage, which bears resemblance to severe acute respiratory syndromes induced by both SARS-CoV and MERS-CoV infections. Although recent papers have highlighted some neuropathologies associated with COVID-19 infection, little is known about this topic of great importance in the area of public health. Here, we discuss how neuroinflammation related to COVID-19 could be triggered by direct viral neuroinvasion and/or cytokine release over the course of the infection.

Potential of application of the RNA interference phenomenon in the treatment of new coronavirus infection COVID-19.

COVID-19 has killed more than 4 million people to date and is the most significant global health problem. The first recorded case of COVID-19 had been noted in Wuhan, China in December 2019, and already on March 11, 2020, World Health Organization declared a pandemic due to the rapid spread of this infection. In addition to the damage to the respiratory system, SARS-CoV-2 is capable of causing severe complications that can affect almost all organ systems. Due to the insufficient effectiveness of the COVID-19 therapy, there is an urgent need to develop effective specific medicines. Among the known approaches to the creation of antiviral drugs, a very promising direction is the development of drugs whose action is mediated by the mechanism of RNA interference (RNAi). A small interfering RNA (siRNA) molecule suppresses the expression of a target gene in this regulatory pathway. The phenomenon of RNAi makes it possible to quickly create a whole series of highly effective antiviral drugs, if the matrix RNA (mRNA) sequence of the target viral protein is known. This review examines the possibility of clinical application of siRNAs aimed at suppressing reproduction of the SARS-CoV-2, taking into account the experience of similar studies using SARS-CoV and MERS-CoV infection models. It is important to remember that the effectiveness of siRNA molecules targeting viral genes may decrease due to the formation of viral resistance. In this regard, the design of siRNAs targeting the cellular factors necessary for the reproduction of SARS-CoV-2 deserves special attention.

Middle East Respiratory Syndrome (MERS) Virus-Pathophysiological Axis and the Current Treatment Strategies.

Middle East respiratory syndrome (MERS) is a lethal respiratory disease with its first case reported back in 2012 (Jeddah, Saudi Arabia). It is a novel, single-stranded, positive-sense RNA beta coronavirus (MERS-CoV) that was isolated from a patient who died from a severe respiratory illness. Later, it was found that this patient was infected with MERS. MERS is endemic to countries in the Middle East regions, such as Saudi Arabia, Jordan, Qatar, Oman, Kuwait and the United Arab Emirates. It has been reported that the MERS virus originated from bats and dromedary camels, the natural hosts of MERS-CoV. The transmission of the virus to humans has been thought to be either direct or indirect. Few camel-to-human transmissions were reported earlier. However, the mode of transmission of how the virus affects humans remains unanswered. Moreover, outbreaks in either family-based or hospital-based settings were observed with high mortality rates, especially in individuals who did not receive proper management or those with underlying comorbidities, such as diabetes and renal failure. Since then, there have been numerous reports hypothesising complications in fatal cases of MERS. Over the years, various diagnostic methods, treatment strategies and preventive measures have been strategised in containing the MERS infection. Evidence from multiple sources implicated that no treatment options and vaccines have been developed in specific, for the direct management of MERS-CoV infection. Nevertheless, there are supportive measures outlined in response to symptom-related management. Health authorities should stress more on infection and prevention control measures, to ensure that MERS remains as a low-level threat to public health.

Comprehensive Comparison of RNA-Seq Data of SARS-CoV-2, SARS-CoV and MERS-CoV Infections: Alternative Entry Routes and Innate Immune Responses.

BackgroundThe pathogenesis of COVID-19 emerges as complex, with multiple factors leading to injury of different organs. Some of the studies on aspects of SARS-CoV-2 cell entry and innate immunity have produced seemingly contradictory claims. In this situation, a comprehensive comparative analysis of a large number of related datasets from several studies could bring more clarity, which is imperative for therapy development.MethodsWe therefore performed a comprehensive comparative study, analyzing RNA-Seq data of infections with SARS-CoV-2, SARS-CoV and MERS-CoV, including data from different types of cells as well as COVID-19 patients. Using these data, we investigated viral entry routes and innate immune responses.Results and ConclusionFirst, our analyses support the existence of cell entry mechanisms for SARS and SARS-CoV-2 other than the ACE2 route with evidence of inefficient infection of cells without expression of ACE2; expression of TMPRSS2/TPMRSS4 is unnecessary for efficient SARS-CoV-2 infection with evidence of efficient infection of A549 cells transduced with a vector expressing human ACE2. Second, we find that innate immune responses in terms of interferons and interferon simulated genes are strong in relevant cells, for example Calu3 cells, but vary markedly with cell type, virus dose, and virus type.

Robust classification-based molecular modelling of diverse chemical entities as potential SARS-CoV-2 3CLpro inhibitors: theoretical justification in light of experimental evidences

ABSTRACT COVID-19 is the most unanticipated incidence of 2020 affecting the human population worldwide. Currently, it is utmost important to produce novel small molecule anti-SARS-CoV-2 drugs urgently that can save human lives globally. Based on the earlier SARS-CoV and MERS-CoV infection along with the general characters of coronaviral replication, a number of drug molecules have been proposed. However, one of the major limitations is the lack of experimental observations with different drug molecules. In this article, 70 diverse chemicals having experimental SARS-CoV-2 3CLproinhibitory activity were accounted for robust classification-based QSAR analysis statistically validated with 4 different methodologies to recognize the crucial structural features responsible for imparting the activity. Results obtained from all these methodologies supported and validated each other. Important observations obtained from these analyses were also justified with the ligand-bound crystal structure of SARS-CoV-2 3CLpro enzyme. Our results suggest that molecules should contain a 2-oxopyrrolidine scaffold as well as a methylene (hydroxy) sulphonic acid warhead in proper orientation to achieve higher inhibitory potency against SARS-CoV-2 3CLpro. Outcomes of our study may be able to design and discover highly effective SARS-CoV-2 3CLpro inhibitors as potential anticoronaviral therapy to crusade against COVID-19.