Targeting TMPRSS2 in SARS-CoV-2 Infection

Predicting susceptibility to COVID-19 infection in patients on maintenance hemodialysis by cross-coupling soluble ACE2 concentration with lymphocyte count: an algorithmic approach

Introduction

Patients on maintenance hemodialysis (MHD) were more vulnerable to and had a higher mortality during the COVID-19 pandemic. As angiotensin converting enzyme 2 (ACE2) and transmembrane protease serine S1 member 2 (TMPRSS2) played crucial roles in viral entry into the human host cells, we therefore investigated in the MHD patients whether their plasma levels were associated with susceptibility to the COVID-19.

Methods

Blood samples were collected from the patients in our then COVID-19 free center immediately upon lifting of the stringent quarantine measures in early December of 2022 and infection situation was observed within the following 2 weeks. Plasma levels of the soluble ACE2 (sACE2), ACE (sACE) and TMPRSS2 (sTMPRSS2) were measured with ELISA method. Data were stepwisely tested for independent effect, relevant role and synergistic action on the susceptibility by multiple logistic regression, receiver operating characteristic curve and multiple dimensionality reduction (MDR) method, respectively.

Results

Among the 174 eligible patients, 95 (54.6%) turned COVID-19 positive with a male to female ratio of 1.57 during the observation period. Comparing with the uninfected, the infected had significantly higher sACE2 and lower sTMPRSS2 levels upon comparable sACE concentration. Besides the sACE2, factors associated with susceptibility were vintage and individual session time of the hemodialysis, smoking and comorbidity of hepatitis, whereas lymphocyte counts showed a tendency (p = 0.052). Patients simultaneously manifesting higher sACE2 level and lower lymphocyte counts had an increased infection risk as confirmed by the MDR method.

Conclusion

By sorting out the susceptible ones expeditiously, this algorithmic approach may help the otherwise vulnerable MHD patients weather over future wave of COVID-19 variants or outbreak of other viral diseases.

SARS-CoV-2 inhibitory potential of fish oil-derived 2-pyrone compounds by acquiring linoleic acid binding site on the spike protein

Traditional medicines have reportedly treated SARS-CoV-2 infection. Substantial evidence shows that fish oil supplements promote human immune function, suggesting they may lessen susceptibility to SARS-CoV-2 infection and suppress viral replication by inducing interferon. Fish oil was subjected to partition chromatography and separated into two compounds (EP01 and DH01). Isolated compounds were purified and characterized using UV, FTIR, NMR, and mass spectrometry to confirm their identity. Molecular docking was studied on the SARS CoV-2 variants of concern; SARS CoV-2 WT (PDB: 6VXX), SARS CoV-2 Alpha variant (PDB: 7LWS), SARS CoV-2 Delta variant (PDB: 7TOU), SARS CoV-2 Gamma variant (PDB: 7V78), SARS CoV-2 Kappa variant (PDB: 7VX9), and SARS CoV-2 Omicron variant (PDB: 7QO7) and TMPRSS2 (PDB: 7Y0E). Further selected protein-ligand complexes were subjected to 100 ns MD simulations to predict their biological potential in the SARS-CoV-2 treatment. In-vitro biological studies were carried out to support in-silico findings. Isolated compounds EP01 and DH01 were identified as 5-Tridecyltetrahydro-2H-pyran-2-one and 5-Heptadecyltetrahydro-2H-pyran-2-one, respectively. The compound EP01 significantly reduced (93.24 %) the viral RNA copy number with an IC50 of ~8.661 μM. EP01 proved to be a potent antiviral by in-vitro method against the SARS-CoV-2 clinical isolate, making it a promising antiviral candidate, with a single dose capable of preventing viral replication.

ACE-2 Blockade & TMPRSS2 Inhibition Mitigate SARS-CoV-2 Severity Following Cigarette Smoke Exposure in Airway Epithelial Cells In Vitro

Cigarette smoking is associated with COVID-19 prevalence and severity, but the mechanistic basis for how smoking alters SARS-CoV-2 pathogenesis is unknown. A potential explanation is that smoking alters the expression of the SARS-CoV-2 cellular receptor and point of entry, angiotensin converting enzyme-2 (ACE-2), and its cofactors including transmembrane protease serine 2 (TMPRSS2). We investigated the impact of cigarette smoking on the expression of ACE-2, TMPRSS2, and other known cofactors of SARS-CoV-2 infection and the resultant effects on infection severity in vitro. Cigarette smoke extract (CSE) exposure increased ACE-2 and TMPRSS2 mRNA expression compared to air control in ferret airway cells, Calu-3 cells, and primary human bronchial epithelial (HBE) cells derived from normal and COPD donors. CSE-exposed ferret airway cells inoculated with SARS-CoV-2 had a significantly higher intracellular viral load versus vehicle-exposed cells. Likewise, CSE-exposure increased both SARS-CoV-2 intracellular viral load and viral replication in both normal and COPD HBE cells over vehicle control. Apoptosis was increased in CSE-exposed, SARS-CoV-2-infected HBE cells. Knockdown of ACE-2 via an antisense oligonucleotide (ASO) reduced SARS-CoV-2 viral load and infection in CSE-exposed ferret airway cells that was augmented by co-administration of camostat mesylate to block TMPRSS2 activity. Smoking increases SARS-CoV-2 infection via upregulation of ACE2 and TMPRSS2.

Sex hormones in COVID-19 severity: The quest for evidence and influence mechanisms

Studies have reported variable effects of sex hormones on serious diseases. Severe disease and mortality rates in COVID-19 show marked gender differences that may be related to sex hormones. Sex hormones regulate the expression of the viral receptors ACE2 and TMPRSS2, which affect the extent of viral infection and consequently cause variable outcomes. In addition, sex hormones have complex regulatory mechanisms that affect the immune response to viruses. These hormones also affect metabolism, leading to visceral obesity and severe disease can result from complications such as thrombosis. This review presents the latest researches on the regulatory functions of hormones in viral receptors, immune responses, complications as well as their role in COVID-19 progression. It also discusses the therapeutic possibilities of these hormones by reviewing the recent findings of clinical and assay studies.

Effect of SARS-CoV-2 infection on semen parameters in sperm bank volunteers with normal sperm concentration

In this study, we aimed to assess the effect of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on semen parameters. The study comprised 110 sperm volunteers who self-reported SARS-CoV-2 infection from the Human Sperm Bank of the Center for Reproductive Medicine, Shandong University (Jinan, China). The volunteers had normal sperm concentration before infection. Each volunteer provided semen samples before and after infection. We selected 90 days after infection as the cutoff point. Semen parameters within 90 days after infection of 109 volunteers (group A) were compared with semen parameters before infection. Moreover, semen parameters on or after 90 days after infection of 36 volunteers (group B) were compared with semen parameters before infection. Furthermore, based on whether the volunteers had completed the three-dose SARS-CoV-2 vaccination booster, volunteers in group A and B were further divided into two subgroups separately. Semen parameters were compared before and after infection in each subgroup. Our results showed that in this cohort population, the semen quality in volunteers with normal sperm concentrations before infection decreased after SARS-CoV-2 infection within 90 days, while the semen quality returned to preinfection levels after 90 days. The completion of a three-dose SARS-CoV-2 vaccination booster may exert a protective effect on semen quality after infection.

ACE2 and TMPRSS2 expression in patients before, during, and after SARS-CoV-2 infection

During the SARS-CoV-2 pandemic angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) were constantly under the scientific spotlight, but most studies evaluated ACE2 and TMPRSS2 expression levels in patients infected by SARS-CoV-2. Thus, this study aimed to evaluate the expression levels of both proteins before, during, and after-infection. For that, nasopharyngeal samples from 26 patients were used to measure ACE2/TMPRSS2 ex-pression via qPCR. Symptomatic patients presented lower ACE2 expression levels before and after the infection than those in asymptomatic patients; however, these levels increased during SARS-CoV-2 infection. In addition, symptomatic patients presented higher expression levels of TMPRSS2 pre-infection, which decreased in the following periods. In summary, ACE2 and TMPRSS2 expression levels are potential risk factors for the development of symptomatic COVID-19, and the presence of SARS-CoV-2 potentially modulates those levels.

Updates in the pathophysiology of COVID-19 infection in male reproductive and sexual health: a literature review

This extensive comprehensive review explores the impact of the Coronavirus disease 2019 (COVID-19) pandemic on men's sexual and reproductive health. We conducted a literature review focusing on the possible pathophysiology by which severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) affects men's sexual and reproductive systems. We reviewed most of the studies that reported the impact of SARS-CoV-2 infection on the Testicular, Epididymal, Prostatic, and Penile tissue. Also, we focused on evaluating the SARS-CoV-2 infection on semen parameters and male reproductive hormones. Finally, we reviewed the COVID-19 vaccine's effect on male reproductive and sexual health. Findings revealed the adverse consequences of SARS-CoV-2 at cellular and organ levels on the male genital tract. However, the reported data are still controversial. The initial data regarding COVID-19 vaccination was promising promoted safety for men's reproductive and sexual health. We conclude this paper by offering recommendations to address these adverse consequences and potentially improve sexual and reproductive health among men in the post-COVID-19 pandemic era.

Triterpenoidal Saponins from the Leaves of Aster koraiensis Offer Inhibitory Activities against SARS-CoV-2

Triterpenoidal saponins have been reported to be able to restrain SARS-CoV-2 infection. To isolate antiviral compounds against SARS-CoV-2 from the leaves of Aster koraiensis, we conducted multiple steps of column chromatography. We isolated six triperpenoidal saponins from A. koraiensis leaves, including three unreported saponins. Their chemical structures were determined using HR-MS and NMR data analyses. Subsequently, we tested the isolates to assess their ability to impede the entry of the SARS-CoV-2 pseudovirus (pSARS-CoV-2) into ACE2+ H1299 cells and found that five of the six isolates displayed antiviral activity with an IC50 value below 10 μM. Notably, one unreported saponin, astersaponin J (1), blocks pSARS-CoV-2 in ACE2+ and ACE2/TMPRSS2+ cells with similar IC50 values (2.92 and 2.96 μM, respectively), without any significant toxic effect. Furthermore, our cell-to-cell fusion and SARS-CoV-2 Spike-ACE2 binding assays revealed that astersaponin J inhibits membrane fusion, thereby blocking both entry pathways of SARS-CoV-2 while leaving the interaction between the SARS-CoV-2 Spike and ACE2 unaffected. Overall, this study expands the list of antiviral saponins by introducing previously undescribed triterpenoidal saponins isolated from the leaves of A. koraiensis, thereby corroborating the potency of triterpenoid saponins in impeding SARS-CoV-2 infection.

Men, testosterone and Covid-19

Men have more severe Coronavirus disease 2019 (Covid-19) outcomes and higher mortality rates than women, and it was suggested that testosterone levels might promote severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and Covid-19 severity. However, clinical studies have not supported this theory. Studies have consistently shown that serum testosterone concentrations during acute Covid-19 in men are inversely proportional to the inflammatory cytokines and severity of illness. It is likely that lower testosterone concentrations in this setting are a result of acute Covid-19 illness on the hypothalamic-pituitary-testicular axis. Clinical trials that attempted to lower testosterone concentrations further or block androgen signaling acutely during Covid-19 in men did not result in improved Covid-19 outcomes. Additionally, pre-existing male hypogonadism, diagnosed before Covid-19 pandemic, was found to be a risk factor for hospitalization from Covid-19. In this review, we also discuss the preclinical and mechanistic studies that have evaluated the role of androgens in SARS-CoV-2 infection and illness. Finally, long-term consequences of Covid-19 on male reproductive health are reviewed. SARS-CoV-2 virus is known to infiltrate testis and induce orchitis in men, but it is unclear if Covid-19 leads to an increase in incidence of male hypogonadism.

Investigation of the mutated antimicrobial peptides to inhibit ACE2, TMPRSS2 and GRP78 receptors of SARS-CoV-2 and angiotensin II type 1 receptor (AT1R) as well as controlling COVID-19 disease

SARS-CoV-2 is a global problem nowadays. Based on studies, some human receptors are involved in binding to SARS-CoV-2. Thus, the inhibition of these receptors can be effective in the treatment of Covid-19. Because of the proven benefits of antimicrobial peptides (AMPs) and the side effects of chemical drugs, they can be known as an alternative to recent medicines. RCSB PDB to obtain PDB id, StraPep and PhytAMP to acquire Bio-AMPs information and 3-D structure, and AlgPred, Toxinpred, TargetAntiAngio, IL-4pred, IL-6pred, ACPred and Hemopred databases were used to find the best score peptide features. HADDOCK 2.2 was used for molecular docking analysis, and UCSF Chimera software version 1.15, SWISS-MODEL and BIOVIA Discovery Studio Visualizer4.5 were used for mutation and structure modeling. Furthermore, MD simulation results were achieved from GROMACS 4.6.5. Based on the obtained results, the Moricin peptide was found to have the best affinity for ACE2. Moreover, Bacteriocin leucocin-A had the highest affinity for GRP78, Cathelicidin-6 had the best affinity for AT1R, and Bacteriocin PlnK had the best binding affinity for TMPRSS2. Additionally, Bacteriocin glycocin F, Bacteriocin lactococcin-G subunit beta and Cathelicidin-6 peptides were the most common compounds among the four receptors. However, these peptides also have some side effects. Consequently, the mutation eliminated the side effects, and MD simulation results indicated that the mutation proved the result of the docking analysis. The effect of AMPs on ACE2, GRP78, TMPRSS2 and AT1R receptors can be a novel treatment for Covid-19.Communicated by Ramaswamy H. Sarma.

Persistent oligonecrozoospermia after asymptomatic SARS-CoV-2 infection. A case report and literature review

COVID-19 is known to have deleterious effects on different systems such as the respiratory, cardiovascular, central nervous, and gastrointestinal. However, conflicting data about the possible implications for male reproductive health and fertility have been reported. In addition, the long-term consequences of SARS-CoV-2 infection remain unclear. Herein, we report a case of a 42-year-old man with no known co-morbidities and normal baseline semen quality, who subsequently suffered an asymptomatic SARS-CoV-2 infection. Shortly after, the patient developed sudden oligoasthenozoospermia, even reaching azoospermia, which gradually evolved into persistent severe oligonecrozoospermia, accompanied by semen inflammation and oxidative stress. Remarkably, the latter occurred in the absence of urogenital infections, hormonal imbalances, tissue/organ obstruction/damage, medication or drug treatment, smoking, or exposure to toxins/pollutants, radiation, or high temperature. This case constitutes valuable clinical evidence that adds to the current knowledge in the field and highlights the need for further and longer follow-up studies to better understand the putative long-term consequences of SARS-CoV-2 infection on male fertility.

Significance of Furin Expression in Thyroid Neoplastic Transformation

Angiotensin-Converting Enzyme 2 (ACE2), Transmembrane Serine Protease 2 (TMPRSS2), and Furin were known to be key players in the SARS-CoV-2 infection, and the thyroid gland was revealed to be one of the relevant targets of the virus. Regardless of the viral infection, the expression of these molecules in the thyroid gland and their putative role in the neoplastic transformation of the thyrocytes has not been thoroughly explored. In this work, we aimed to characterize the mRNA and protein expression pattern of ACE2, TMPRSS2, and Furin in a series of patients with thyroid lesions. Our main results revealed a significantly decreased expression of ACE2 mRNA in the thyroid neoplasms in comparison to normal adjacent tissue. Furin mRNA was significantly increased in thyroid neoplasms when compared to normal adjacent tissue. In addition, a higher Furin mRNA level in thyroid carcinomas was associated with the presence of lymph node metastasis. Furin mRNA expression revealed a high discriminatory power between adjacent tissue and neoplasms. Protein expression of these molecules did not correlate with mRNA expression. Our study shows the mRNA downregulation of ACE2 and overexpression of Furin in thyroid neoplasms. Further studies are required to clarify if Furin expression can be a potential diagnostic indicator in thyroid neoplasia.

Viruses, bacteria and parasites: infection of the male genital tract and fertility

BACKGROUND

Infertility affects one couple out of six worldwide. Male infertilty can result from congenital or acquired factors, of which pathogens that reach the genital tract through sexual contact or blood dissemination. The impact of major viral, bacterial and parasitic infections on the male genital tract and fertility has been summarized.

RESULTS AND CONCLUSIONS

A systematic review of articles published in the Google Scholar and PubMed databases was conducted. It turns out that viruses, as well as bacteria and parasites are major inducers of male genital tract infections and ensuing infertility through damage to the organs and subsequent loss of function and/or through direct damage to the sperm cells. Moreover, not only male infertility results from such infections but these can also be transmitted to women and even to the offspring, thus highlighting the need to efficiently detect, treat and prevent them.

COVID-19 associates with semen inflammation and sperm quality impairment that reverses in the short term after disease recovery

Introduction: COVID-19 exerts deleterious effects on the respiratory, cardiovascular, gastrointestinal, and central nervous systems, causing more severe disease in men than in women. However, cumulative reported data about the putative consequences on the male reproductive tract and fertility are controversial. Furthermore, the long-term effects of SARS-CoV-2 infection are still uncertain. Methods: In this study, we prospectively evaluated levels of inflammatory cytokines and leukocytes in semen and sperm quality parameters in a cohort of 231 reproductive-aged male patients, unvaccinated, who had recovered from mild or severe COVID-19 and in 62 healthy control individuals. Sperm quality was assessed early (less than 3 months) and long (more than 3 and up to 6 months) after having COVID-19. Interestingly, and unlike most reported studies, available extensive background and baseline data on patients' sperm quality allowed performing a more accurate analysis of COVID-19 effects on sperm quality. Results: Significantly higher levels of IL-1β, TNF and IFNγ were detected in semen from patients recently recovered from mild and/or severe COVID-19 with respect to control individuals indicating semen inflammation. Moreover, patients recovered from mild and/or severe COVID-19 showed significantly reduced semen volume, lower total sperm counts, and impaired sperm motility and viability. Interestingly, all observed alterations returned to baseline values after 3 or more months after disease recovery. Discussion: These results indicate that COVID-19 associates with semen inflammation and impaired semen quality early after disease. However, long COVID-19 seems not to include long-term detrimental consequences on male fertility potential since the observed alterations were reversible after 1-2 spermatogenesis cycles. These data constitute compelling evidence allowing a better understanding of COVID-19 associated sequelae, fundamental for semen collection in assisted reproduction.

Association of SARS-CoV-2 Infection During Controlled Ovarian Stimulation With Oocyte- and Embryo-Related Outcomes

Importance

SARS-CoV-2 infection has had significant effects on the health of people worldwide. Whether SARS-CoV-2 infection during controlled ovarian stimulation (COS) is associated with laboratory outcomes in assisted reproductive technology remains unclear.

Objective

To investigate the association between SARS-CoV-2 infection during COS with oocyte- and embryo-related outcomes.

Design, Setting, and Participants

A multicenter cohort study was conducted of couples undergoing assisted reproductive technology treatments in 7 reproductive centers in 4 provinces in China from October 1, 2022, to December 31, 2022. All couples received nucleic acid testing for SARS-CoV-2 during COS. The SARS-CoV-2-positive group included couples in which either partner was infected with SARS-CoV-2. The SARS-CoV-2-negative group comprised couples without infection.

Exposure

In the SARS-CoV-2-positive group, either partner was infected with SARS-CoV-2 during COS, defined as a positive test result for the SARS-CoV-2 antigen.

Main Outcomes and Measures

Primary outcomes were the available embryo and blastocyst and top-quality embryo and blastocyst rates. Secondary outcomes were the number of oocytes retrieved, the mature oocyte rate, normal fertilization (2 pronuclei observed on day 1 after insemination [2PN]), oocyte degeneration, 2PN cleavage, and blastocyst formation rates.

Results

A total of 585 heterosexual couples with infertility participated in the study (median [IQR] age for female partners, 33 [30-37] years), with 135 couples in the SARS-CoV-2-positive group and 450 in the SARS-CoV-2-negative group. The characteristics of the groups were similar. The SARS-CoV-2-positive group had a significantly lower top-quality embryo rate (odds ratio [OR], 0.83; 95% CI, 0.71-0.96), top-quality blastocyst rate (OR, 0.59; 95% CI, 0.45-0.77), available blastocyst rate (OR, 0.70; 95% CI, 0.59-0.82), and blastocyst formation rate (OR, 0.61; 95% CI, 0.52-0.71) than the SARS-CoV-2-negative group. Analysis of the associations of infection by sex showed that the female positive group had impaired oocyte and embryo quality regarding mature oocyte rate, 2PN cleavage rate, top-quality embryo rate, blastocyst formation rate, available blastocyst rate, and top-quality blastocyst rate compared with the SARS-CoV-2-negative group. Compared with the SARS-CoV-2-negative group, the male positive group and the group of couples with both positive partners had significantly decreased available blastocyst rate, top-quality blastocyst rate, and blastocyst formation rate compared with the SARS-CoV-2 negative group.

Conclusions and Relevance

In this cohort study, SARS-CoV-2 infection during COS was negatively associated with embryo and blastocyst quality. Reproductive physicians should be more attentive to patients with SARS-CoV-2 infection during COS and should give couples who have been infected adequate counseling.

Efficacy and safety of proxalutamide (GT0918) in severe or critically ill patients with COVID-19: study protocol for a prospective, open-label, single-arm, single-center exploratory trial

BACKGROUND

The rapid worldwide spread of COVID-19 has caused a global health challenge with high mortality of severe or critically ill patients with COVID-19. To date, there is no specific efficient therapeutics for severe or critically ill patients with COVID-19. It has been reported that androgen is related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Proxalutamide as an androgen receptor antagonist has shown potential treatment effects on COVID-19 patients. Thus, this trial is designed to investigate the efficacy and safety of proxalutamide in severe or critically ill patients with COVID-19.

METHODS

This single-arm, open-label, single-center prospective exploratory trial is planned to recruit 64 severe or critically ill patients with COVID-19 in China. Recruitment started on 16 May 2022 and is foreseen to end on 16 May 2023. Patients will be followed-up until 60 days or death, whichever comes first. The primary outcome is the 30-day all-cause mortality. Secondary endpoints included 60-day all-cause mortality, rate of clinical deterioration within 30 days after administration, time to sustain clinical recovery (determined using an 8-point ordinal scale), mean change in the Acute Physiology and Chronic Health Evaluation II scores, change in oxygenation index, changes in chest CT scan, percentage of patients confirmed negative for SARS-CoV-2 by nasopharyngeal swab, change in Ct values of SARS-CoV-2 and safety. Visits will be performed on days 1 (baseline), 15 or 30, 22, and 60.

DISCUSSION

The trial is the first to investigate the efficacy and safety of proxalutamide in severe or critically ill patients with COVID-19. The findings of this study might lead to the development of better treatment for COVID-19 and provide convincing evidence regarding the efficacy and safety of proxalutamide.

TRIAL REGISTRATION

This study was registered on 18 June 2022 at the Chinese Clinical Trial Registry (ChiCTR2200061250).

ACE2 Receptor and TMPRSS2 Protein Expression Patterns in the Human Brainstem Reveal Anatomical Regions Potentially Vulnerable to SARS-CoV-2 Infection

Angiotensin-converting enzyme 2 receptor (ACE2R) is a transmembrane protein expressed in various tissues throughout the body that plays a key role in the regulation of blood pressure. Recently, ACE2R has gained significant attention due to its involvement in the pathogenesis of COVID-19, the disease caused by the Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2). While ACE2 receptors serve as entry points for the novel coronavirus, Transmembrane Serine Protease 2 (TMPRSS2), an enzyme located on the cell membrane, is required for SARS-CoV-2 S protein priming. Even though numerous studies have assessed the effects of COVID-19 on the brain, very little information is available concerning the distribution of ACE2R and TMPRSS2 in the human brain, with particular regard to their topographical expression in the brainstem. In this study, we investigated the expression of ACE2R and TMPRSS2 in the brainstem of 18 adult subjects who died due to pneumonia/respiratory insufficiency. Our findings indicate that ACE2R and TMPRSS2 are expressed in neuronal and glial cells of the brainstem, particularly at the level of the vagal nuclei of the medulla and the midbrain tegmentum, thus confirming the expression and anatomical localization of these proteins within specific human brainstem nuclei. Furthermore, our findings help to define anatomically susceptible regions to SARS-CoV-2 infection in the brainstem, advancing knowledge on the neuropathological underpinnings of neurological manifestations in COVID-19.

A comprehensive overview on the transmission, pathogenesis, diagnosis, treatment, and prevention of SARS-CoV-2

Severe acute respiratory syndrome coronavirus (SARS-CoV) is a single positive-strand RNA virus that is responsible for the current pandemic that the world has been facing since 2019. The primary route of transmission of SARS-CoV-2 is through respiratory tract transmission. However, other transmission routes such as fecal-oral, vertical transmission, and aerosol-eye also exist. In addition, it has been found that the pathogenesis of this virus involves the binding of the virus's S protein to its host cell surface receptor angiotensin-converting enzyme 2, which results in the subsequent membrane fusion that is required for SARS-CoV-2 to replicate and complete its entire life. The clinical symptoms of patients infected with SARS-CoV-2 can range from asymptomatic to severe. The most common symptoms seen include fever, dry cough, and fatigue. Once these symptoms are observed, a nucleic acid test is done using reverse transcription-polymerase chain reaction. This currently serves as the main confirmatory tool for COVID-19. Despite the fact that no cure has been found for SARS-CoV-2, prevention methods such as vaccines, specific facial mask, and social distancing have proven to be quite effective. It is imperative to have a complete understanding of the transmission and pathogenesis of this virus. To effectively develop new drugs as well as diagnostic tools, more knowledge about this virus would be needed.

Sex hormones in SARS-CoV-2 susceptibility: key players or confounders?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has a clear sex disparity in clinical outcomes. Hence, the interaction between sex hormones, virus entry receptors and immune responses has attracted major interest as a target for the prevention and treatment of SARS-CoV-2 infections. This Review summarizes the current understanding of the roles of androgens, oestrogens and progesterone in the regulation of virus entry receptors and disease progression of coronavirus disease 2019 (COVID-19) as well as their therapeutic value. Although many experimental and clinical studies have analysed potential mechanisms by which female sex hormones might provide protection against SARS-CoV-2 infectivity, there is currently no clear evidence for a sex-specific expression of virus entry receptors. In addition, reports describing an influence of oestrogen, progesterone and androgens on the course of COVID-19 vary widely. Current data also do not support the administration of oestradiol in COVID-19. The conflicting evidence and lack of consensus results from a paucity of mechanistic studies and clinical trials reporting sex-disaggregated data. Further, the influence of variables beyond biological factors (sex), such as sociocultural factors (gender), on COVID-19 manifestations has not been investigated. Future research will have to fill this knowledge gap as the influence of sex and gender on COVID-19 will be essential to understanding and managing the long-term consequences of this pandemic.

Receptors and Cofactors That Contribute to SARS-CoV-2 Entry: Can Skin Be an Alternative Route of Entry?

To prevent the spread of SARS-CoV-2, all routes of entry of the virus into the host must be mapped. The skin is in contact with the external environment and thus may be an alternative route of entry to transmission via the upper respiratory tract. SARS-CoV-2 cell entry is primarily dependent on ACE2 and the proteases TMPRSS2 or cathepsin L but other cofactors and attachment receptors have been identified that may play a more important role in specific tissues such as the skin. The continued emergence of new variants may also alter the tropism of the virus. In this review, we summarize current knowledge on these receptors and cofactors, their expression profile, factors modulating their expression and their role in facilitating SARS-CoV-2 infection. We discuss their expression in the skin and their possible involvement in percutaneous infection since the presence of the virus has been detected in the skin.

Ferrets: A powerful model of SARS-CoV-2

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in recent years not only caused a global pandemic but resulted in enormous social, economic, and health burdens worldwide. Despite considerable efforts to combat coronavirus disease 2019 (COVID-19), various SARS-CoV-2 variants have emerged, and their underlying mechanisms of pathogenicity remain largely unknown. Furthermore, effective therapeutic drugs are still under development. Thus, an ideal animal model is crucial for studying the pathogenesis of COVID-19 and for the preclinical evaluation of vaccines and antivirals against SARS-CoV-2 and variant infections. Currently, several animal models, including mice, hamsters, ferrets, and non-human primates (NHPs), have been established to study COVID-19. Among them, ferrets are naturally susceptible to SARS-CoV-2 infection and are considered suitable for COVID-19 study. Here, we summarize recent developments and application of SARS-CoV-2 ferret models in studies on pathogenesis, therapeutic agents, and vaccines, and provide a perspective on the role of these models in preventing COVID-19 spread.

SARS-CoV-2, fertility and assisted reproduction

BACKGROUND

In 2020, SARS-CoV-2 and the COVID-19 pandemic had a huge impact on the access to and provision of ART treatments. Gradually, knowledge of the virus and its transmission has become available, allowing ART activities to resume. Still, questions on the impact of the virus on human gametes and fertility remain.

OBJECTIVE AND RATIONALE

This article summarizes published data, aiming to clarify the impact of SARS-CoV-2 and the COVID-19 disease on human fertility and assisted reproduction, as well as the impact of vaccination, and from this, provide answers to questions that are relevant for people contemplating pregnancy and for health care professionals.

SEARCH METHODS

PUBMED/MEDLINE and the WHO COVID-19 database were searched from inception to 5 October 2022 with search terms focusing on 'SARS-CoV-2' and gametes, embryos, reproductive function, fertility and ART. Non-English studies and papers published prior to 2020 were excluded, as well as reviews and non-peer reviewed publications. Full papers were assessed for relevance and quality, where feasible.

OUTCOMES

From the 148 papers included, the following observations were made. The SARS-CoV-2-binding proteins, angiotensin-converting enzyme 2 (ACE2) and type II transmembrane serine protease (TMPRSS2), are expressed in the testis, but co-expression remains to be proven. There is some evidence of SARS-CoV-2 RNA in the ejaculate of COVID-19 patients with severe disease, but not in those with mild/moderate disease. SARS-CoV-2 infection can impair spermatogenesis, but this seems to resolve after one spermatogenic cycle. Testosterone levels seem to be lower during and after COVID-19, but long-term data are lacking; disease severity may be associated with testosterone levels. COVID-19 cannot be considered a sexually transmitted disease. There is no co-expression of ACE2 and TMPRSS2 in the myometrium, uterus, ovaries or fallopian tubes. Oocytes seem to have the receptors and protease machinery to be susceptible to SARS-CoV-2 infection; however, viral RNA in oocytes has not been detected so far. Women contemplating pregnancy following COVID-19 may benefit from screening for thyroid dysfunction. There is a possible (transient) impact of COVID-19 on menstrual patterns. Embryos, and particularly late blastocysts, seem to have the machinery to be susceptible to SARS-CoV-2 infection. Most studies have not reported a significant impact of COVID-19 on ovarian reserve, ovarian function or follicular fluid parameters. Previous asymptomatic or mild SARS-CoV-2 infection in females does not seem to negatively affect laboratory and clinical outcomes of ART. There are no data on the minimum required interval, if any, between COVID-19 recovery and ART. There is no evidence of a negative effect of SARS-CoV-2 vaccination on semen parameters or spermatogenesis, ovarian function, ovarian reserve or folliculogenesis. A transient effect on the menstrual cycle has been documented. Despite concerns, cross reactivity between anti-SARS-CoV-2 spike protein antibodies and Syncytin-1, an essential protein in human implantation, is absent. There is no influence of mRNA SARS-CoV-2 vaccine on patients' performance during their immediate subsequent ART cycle. Pregnancy rates post-vaccination are similar to those in unvaccinated patients.

WIDER IMPLICATIONS

This review highlights existing knowledge on the impact of SARS-CoV-2 infection or COVID-19 on fertility and assisted reproduction, but also identifies gaps and offers suggestions for future research. The knowledge presented should help to provide evidence-based advice for practitioners and couples contemplating pregnancy alike, facilitating informed decision-making in an environment of significant emotional turmoil.

Therapeutic potential of bromhexine for acute itch in mice: Involvement of TMPRSS2 and kynurenine pathway

Itching is an unpleasant sensation on the skin that could negatively impact the quality of life. Over the years, many non-pharmacological and pharmacological approaches have been introduced to mitigate this burdensome condition; However, the effectiveness of these methods remains questioned. Bromhexine, derived from the Adhatoda vasica plant, is a safe drug with minimal side effects. It has been widely used in managing respiratory symptoms over the years. The results of our study revealed that bromhexine has the potential to alleviate acute itch induced by Compound 48/80, a known mast cell destabilizer. According to our findings, bromhexine exerts its antipruritic effects primarily by inhibiting the Transmembrane Protein Serine Protease 2 (TMPRSS2) and, to a lesser extent, by decreasing the activation of the Kynurenine Pathway (KP). We further investigated the KP involvement by administrating 1-Methyl Tryptophan (1-MT), a known indoleamine-2,3-dioxygenase (IDO) inhibitor. 1-MT was found to be effective in reducing the itch itself. Moreover, co-administration of bromhexine and 1-MT resulted in synergistic antipruritic effects, suggesting that KP plays a role in acute itch. To conclude, we have presented for the first time a repositioning of bromhexine as a treatment for acute itch. In addition, we addressed the involvement of TMPRSS2 and KP in this process.

Potential molecular mechanisms of chronic fatigue in long haul COVID and other viral diseases

Historically, COVID-19 emerges as one of the most devastating diseases of humankind, which creates an unmanageable health crisis worldwide. Until now, this disease costs millions of lives and continues to paralyze human civilization's economy and social growth, leaving an enduring damage that will take an exceptionally long time to repair. While a majority of infected patients survive after mild to moderate reactions after two to six weeks, a growing population of patients suffers for months with severe and prolonged symptoms of fatigue, depression, and anxiety. These patients are no less than 10% of total COVID-19 infected individuals with distinctive chronic clinical symptomatology, collectively termed post-acute sequelae of COVID-19 (PASC) or more commonly long-haul COVID. Interestingly, Long-haul COVID and many debilitating viral diseases display a similar range of clinical symptoms of muscle fatigue, dizziness, depression, and chronic inflammation. In our current hypothesis-driven review article, we attempt to discuss the molecular mechanism of muscle fatigue in long-haul COVID, and other viral diseases as caused by HHV6, Powassan, Epstein-Barr virus (EBV), and HIV. We also discuss the pathological resemblance of virus-triggered muscle fatigue with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Interaction of copper potential metallodrugs with TMPRSS2: A comparative study of docking tools and its implications on COVID-19

SARS-CoV-2 is the virus responsible for the COVID-19 pandemic. For the virus to enter the host cell, its spike (S) protein binds to the ACE2 receptor, and the transmembrane protease serine 2 (TMPRSS2) cleaves the binding for the fusion. As part of the research on COVID-19 treatments, several Casiopeina-analogs presented here were looked at as TMPRSS2 inhibitors. Using the DFT and conceptual-DFT methods, it was found that the global reactivity indices of the optimized molecular structures of the inhibitors could be used to predict their pharmacological activity. In addition, molecular docking programs (AutoDock4, Molegro Virtual Docker, and GOLD) were used to find the best potential inhibitors by looking at how they interact with key amino acid residues (His296, Asp 345, and Ser441) in the catalytic triad. The results show that in many cases, at least one of the amino acids in the triad is involved in the interaction. In the best cases, Asp435 interacts with the terminal nitrogen atoms of the side chains in a similar way to inhibitors such as nafamostat, camostat, and gabexate. Since the copper compounds localize just above the catalytic triad, they could stop substrates from getting into it. The binding energies are in the range of other synthetic drugs already on the market. Because serine protease could be an excellent target to stop the virus from getting inside the cell, the analyzed complexes are an excellent place to start looking for new drugs to treat COVID-19.

Risk Factors of Severe COVID-19: A Review of Host, Viral and Environmental Factors

The clinical course and outcome of COVID-19 are highly variable, ranging from asymptomatic infections to severe disease and death. Understanding the risk factors of severe COVID-19 is relevant both in the clinical setting and at the epidemiological level. Here, we provide an overview of host, viral and environmental factors that have been shown or (in some cases) hypothesized to be associated with severe clinical outcomes. The factors considered in detail include the age and frailty, genetic polymorphisms, biological sex (and pregnancy), co- and superinfections, non-communicable comorbidities, immunological history, microbiota, and lifestyle of the patient; viral genetic variation and infecting dose; socioeconomic factors; and air pollution. For each category, we compile (sometimes conflicting) evidence for the association of the factor with COVID-19 outcomes (including the strength of the effect) and outline possible action mechanisms. We also discuss the complex interactions between the various risk factors.

The oral manifestations and related mechanisms of COVID-19 caused by SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) was reported to be associated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, and patients present mostly with respiratory symptoms. There have been an increasing number of reports on oral manifestations, and some of these signs are informative in terms of identifying SARS-CoV-2 infection. The goal of present study was to review and synthesize the clinical characteristics and underlying mechanisms of COVID-19 oral manifestations, as well as to evaluate the factors influencing SARS-CoV-2 infectivity, in order to conduct further in-depth investigations and help clinicians diagnose COVID-19 patients exhibiting oral symptoms.

Clinical Application of Antibody Immunity Against SARS-CoV-2: Comprehensive Review on Immunoassay and Immunotherapy

The current COVID-19 global pandemic poses immense challenges to global health, largely due to the difficulty to detect infection in the early stages of the disease, as well as the current lack of effective antiviral therapy. Research and understanding of the human immune system can provide important theoretical and technical support for the clinical diagnosis and treatment of COVID-19, the clinical implementations of which include immunoassays and immunotherapy, which play a crucial role in the fight against the pandemic. This review consolidates the current scientific evidence for immunoassay, which includes multiple methods of detecting antigen and antibody against SARS-CoV-2. We compared the characteristics, advantages and disadvantages, and clinical applications of these three detection techniques. In addition to detecting viral infections, knowledge on the body's immunity against the virus is desirable; thus, the immunotherapy-based neutralizing antibody (nAb) detection methods were discussed. We also gave a brief introduction to the new immunoassay technology such as biosensing. This was followed by an in-depth and extensive review on a variety of immunotherapy methods. It includes convalescent plasma therapy, neutralizing antibody-based treatments targeting different regions of SARS-CoV-2, immunotherapy targeted on the host cell including inhibiting the host cell receptor and cytokine storm, as well as cocktail antibodies, cross-neutralizing antibodies, and immunotherapy based on cross-reactivity between viral epitopes and autoepitopes and autoantibody. Despite the development of various immunological testing methods and antibody therapies, the current global situation of COVID-19 is still tense. We need more efficient detection methods and more reliable antibody therapies. The up-to-date knowledge on therapeutic strategies will likely help clinicians worldwide to protect patients from life-threatening viral infections.

Previous infection with SARS-CoV-2 impacts embryo morphokinetics but not clinical outcomes in a time-lapse imaging system

The goal for the present study was to investigate whether previous infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may compromise embryo morphokinetics and implantation. For that, a historical cohort study was performed in a private university-affiliated in vitro fertilization center. The study included 1628 embryos from 88 patients undergoing intracytoplasmic sperm injection (ICSI) cycles. Patients were age-matched in a 1:3 ratio to either a coronavirus disease (COVID) group, including patients with a positive SARS-CoV-2 immunoglobulin test (n = 22 patients, 386 embryos), or a control group, including patients with a negative SARS-CoV-2 immunoglobulin test (n = 66, 1242 embryos). The effect of previous infection with SARS-CoV-2 on morphokinetic events and ICSI outcomes was evaluated. Embryos derived from patients in the COVID group presented longer time to pronuclei appearance and fading, time to form two, three, four and five cells, and time to blastulation. The durations of the third cell cycle and to time to complete synchronous divisions were also significantly increased in the COVID group compared with the control group, whereas known implantation diagnosis score Day 5 ranked significantly lower in the COVID group. No differences were observed between the COVID and control groups on clinical outcomes. In conclusion, patients planning parenthood, who have recovered from COVID-19 infection, must be aware of a possible effect of the infection on embryo development potential.

Advances of CRISPR-Cas13 system in COVID-19 diagnosis and treatment

The ongoing global pandemic of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in over 570 million infections and 6 million deaths worldwide. Early detection and quarantine are essential to arrest the spread of the highly contagious COVID-19. High-risk groups, such as older adults and individuals with comorbidities, can present severe symptoms, including pyrexia, pertussis, and acute respiratory distress syndrome, on SARS-CoV-2 infection that can prove fatal, demonstrating a clear need for high-throughput and sensitive platforms to detect and eliminate SARS-CoV-2. CRISPR-Cas13, an emerging CRISPR system targeting RNA with high specificity and efficiency, has recently drawn much attention for COVID-19 diagnosis and treatment. Here, we summarized the current research progress on CRISPR-Cas13 in COVID-19 diagnosis and treatment and highlight the challenges and future research directions of CRISPR-Cas13 for effectively counteracting COVID-19.

Thyrotropin Levels in Patients with Coronavirus Disease 2019: Assessment during Hospitalization and in the Medium Term after Discharge

BACKGROUND

The objectives of this study were (1) to compare TSH levels between inpatients with critical versus non-critical coronavirus disease 19 (COVID-19), and (2) to describe the status of TSH levels three months after hospitalization.

METHODS

We collected data on adult patients hospitalized with COVID-19 at Amiens University Hospital. We compared TSH levels between inpatients with critical (intensive care unit admission and/or death) versus non-critical COVID-19. Thereafter, survivors were invited to return for a three-month post-discharge visit where thyroid function tests were performed, regardless of the availability of TSH measurement during hospitalization.

RESULTS

Among 448 inpatients with COVID-19, TSH assay data during hospitalization were available for 139 patients without prior thyroid disease. Patients with critical and non-critical forms of COVID-19 did not differ significantly with regard to the median (interquartile range) TSH level (0.96 (0.68-1.71) vs. 1.27 mIU/L (0.75-1.79), p = 0.40). Abnormal TSH level was encountered in 17 patients (12.2%); most of them had subclinical thyroid disease. TSH assay data at the three-month post-discharge visit were available for 151 patients without prior thyroid disease. Only seven of them (4.6%) had abnormal TSH levels. Median TSH level at the post-discharge visit was significantly higher than median TSH level during hospitalization.

CONCLUSIONS

Our findings suggest that COVID-19 is associated with a transient suppression of TSH in a minority of patients regardless of the clinical form. The higher TSH levels three months after COVID-19 might suggest recovery from non-thyroidal illness syndrome.

Bioinformatics analysis reveals molecular connections between non-alcoholic fatty liver disease (NAFLD) and COVID-19

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 has devastatingly impacted people's lives. Non-alcoholic fatty liver disease (NAFLD) is fatal comorbidity of COVID-19 seen with potential risk factors to develop severe symptoms. This research focuses on determining and elucidating the molecular factors and connections that might contribute to the severity of SARS-CoV-2 infection in NAFLD patients. Here, we comprehensively inspected the genes involved in NAFLD and SARS-CoV-2 entry factors (SCEFs) found by searching through the DisGeNet database and literature review, respectively. Further, we identified the SCEFs-related proteins through protein-protein interaction (PPI) network construction, MCODE, and Cytohubba. Next, the shared genes involved in NAFLD and SARS-CoV-2 entry, and hub gene were determined, followed by the GO and KEGG pathways analysis. X2K database was used to construct the upstream regulatory network of hub genes, as well as to identify the top ten candidates of transcription factors (TFs) and protein kinases (PKs). PPI analysis identified connections between 4 top SCEFs, including ACE, ADAM17, DPP4, and TMPRSS2 and NAFLD-related genes such as ACE, DPP4, IL-10, TNF, and AKT1. GO and KEGG analysis revealed the top ten biological processes and pathways, including cytokine-mediated signaling, PI3K-Akt, AMPK, and mTOR signaling pathways. The upstream regulatory network revealed that AKT1 and MAPK14 as important PKs and HIF1A and SP1 as important TFs associated with AKT1, IL-10, and TNF. The molecular connections identified between COVID-19 and NAFLD may shed light on discovering the causes of the severity of SARS-CoV-2 infected NAFLD patients.

rs12329760 Polymorphism in Transmembrane Serine Protease 2 Gene and Risk of Coronavirus Disease 2019 Mortality

The protease produced by the transmembrane serine protease 2 (TMPRSS2) gene enhances viral infections and has been linked to severe acute respiratory syndrome coronavirus 2 pathogenesis. Therefore, this study evaluated the association between TMPRSS2 and coronavirus disease 2019 (COVID-19) mortality. TMPRSS2 rs12329760 polymorphism was genotyped using the tetraprimer amplification refractory mutation system-polymerase chain reaction method in 592 dead and 693 improved patients. In the current study, the frequency of TMPRSS2 rs12329760 CC than TT genotypes was significantly lower in improved patients than in dead patients. According to the findings of the multivariate logistic regression test, higher levels of mean age, creatinine, erythrocyte sedimentation rate, C-reactive protein, aspartate aminotransferase, lower levels of 25-hydroxyvitamin D, uric acid, and real-time PCR Ct values and TMPRSS2 rs12329760 CC genotype were observed to be associated with increased COVID-19 mortality rates. In conclusion, the TMPRSS2 rs12329760 CC genotype was a polymorphism linked to a significantly higher incidence of severe COVID-19. Further studies are required to corroborate the obtained findings.

Molecular and cellular mechanisms involved in tissue-specific metabolic modulation by SARS-CoV-2

Coronavirus disease 2019 (COVID-19) is triggered by the SARS-CoV-2, which is able to infect and cause dysfunction not only in lungs, but also in multiple organs, including central nervous system, skeletal muscle, kidneys, heart, liver, and intestine. Several metabolic disturbances are associated with cell damage or tissue injury, but the mechanisms involved are not yet fully elucidated. Some potential mechanisms involved in the COVID-19-induced tissue dysfunction are proposed, such as: (a) High expression and levels of proinflammatory cytokines, including TNF-α IL-6, IL-1β, INF-α and INF-β, increasing the systemic and tissue inflammatory state; (b) Induction of oxidative stress due to redox imbalance, resulting in cell injury or death induced by elevated production of reactive oxygen species; and (c) Deregulation of the renin-angiotensin-aldosterone system, exacerbating the inflammatory and oxidative stress responses. In this review, we discuss the main metabolic disturbances observed in different target tissues of SARS-CoV-2 and the potential mechanisms involved in these changes associated with the tissue dysfunction.

Analysis of ACE2 and TMPRSS2 coding variants as a risk factor for SARS-CoV-2 from 946 whole-exome sequencing data in the Turkish population

Heterogeneity in symptoms associated with COVID-19 in infected patients remains unclear. ACE2 and TMPRSS2 gene variants are considered possible risk factors for COVID-19. In this study, a retrospective comparative genome analysis of the ACE2 and TMPRSS2 variants from 946 whole-exome sequencing data was conducted. Allele frequencies of all variants were calculated and filtered to remove variants with allele frequencies lower than 0.003 and to prioritize functional coding variants. The majority of detected variants were intronic, only two ACE2 and three TMPRSS2 nonsynonymous variants were detected in the analyzed cohort. The main ACE2 variants that putatively have a protective or susceptibility effect on SARS-CoV-2 have not yet been determined in the Turkish population. The Turkish genetic makeup likely lacks any ACE2 variant that increases susceptibility to SARS-CoV-2 infection. TMPRSS2 rs75603675 and rs12329760 variants that were previously defined as common variants that have different allele frequencies among populations and may have a role in SARS-CoV-2 attachment to host cells were determined in the population. Overall, these data will contribute to the formation of a national variation database and may also contribute to further studies of ACE2 and TMPRSS2 in the Turkish population and differences in SARS-CoV-2 infection among other populations.

Endoplasmic reticulum secretory pathway: Potential target against SARS-CoV-2

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has recently emerged throughout the world, resulting in more than 400 million cases and over 6 million deaths worldwide as of January 2022. Coronaviruses subvert or use certain aspects of the unfolded protein response in the endoplasmic reticulum to overcome protein translation shutdown to benefit their replication. New virions use the ER-Golgi intermediate compartment to assemble and gain transportation to the cell membrane. Extensive remodeling of the ER has been demonstrated during SARS-CoV-2 infection. In this review article, we discuss the role of the endoplasmic reticulum secretory pathway in the replication cycle of SARS-CoV-2. Currently, there is a dearth of therapeutic options for intervening with SARS-CoV-2 infection. To accelerate drug development, efforts around the globe have been focusing on repurposing drugs that have already been approved for clinical use by regulatory agencies. Targeting the ERS pathway is reasonable, as prior work has shown that SARS-CoV-2 egress is dependent on this pathway. Here we discuss the feasibility of off-patent, FDA-approved, pharmacological inhibitors of the ERS pathway to suppress the SARS-CoV-2 replication cycle, a promising approach that warrants investigation.

Human genetic basis of severe or critical illness in COVID-19

Coronavirus Disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to considerable morbidity and mortality worldwide. The clinical manifestation of COVID-19 ranges from asymptomatic or mild infection to severe or critical illness, such as respiratory failure, multi-organ dysfunction or even death. Large-scale genetic association studies have indicated that genetic variations affecting SARS-CoV-2 receptors (angiotensin-converting enzymes, transmembrane serine protease-2) and immune components (Interferons, Interleukins, Toll-like receptors and Human leukocyte antigen) are critical host determinants related to the severity of COVID-19. Genetic background, such as 3p21.31 and 9q34.2 loci were also identified to influence outcomes of COVID-19. In this review, we aimed to summarize the current literature focusing on human genetic factors that may contribute to the observed diversified severity of COVID-19. Enhanced understanding of host genetic factors and viral interactions of SARS-CoV-2 could provide scientific bases for personalized preventive measures and precision medicine strategies.

SARS-CoV-2 and Skin: New Insights and Perspectives

The SARS-CoV-2 pandemic has disrupted global health systems and brought the entire globe to its knees. Although born as a disease of the respiratory system, COVID-19 can affect different parts of the body, including the skin. Reports of ongoing skin manifestations of COVID-19 have gradually multiplied, pushing researchers to investigate the etiopathogenic mechanisms underlying these phenomena in more depth. In an attempt to investigate the possible association between SARS-CoV-2, ACE2, TMPRSS2 and skin manifestations, we performed immunohistochemical investigations of the ACE2 receptor and TMPRSS2 in nine skin samples from SARS-CoV-2-positive patients compared to a cohort of healthy controls. Furthermore, after consulting public databases regarding ACE2 mRNA expression in various cell populations resident in the skin, we conducted a literature review aimed at outlining the current state of this topic. We did not find statistically different immuno-expression of ACE2 and TMPRSS2 between the group of SARS-CoV-2-positive patients (nine skin biopsies) and the control group. Regarding ACE2, major immunolabeling was present in the epidermal keratinocytes and, rarely, in the fibroblasts and in the adenomeres of the eccrine sweat glands. Regarding the immune expression of TMPRSS2, we found no significant differences between the two groups, with a weak immune staining only in some skin cytotypes. From the review of the literature, we isolated 35 relevant articles according to the inclusion criteria adopted. ACE2 appears to be a target of SARS-CoV-2, although, other receptor molecules may potentially be implicated, such as TMPRSS2. Future studies with large cases and different molecular investigative methods are needed to further elucidate the mechanisms underlying the skin manifestations of SARS-CoV-2.

Effects of Varying Glucose Concentrations on ACE2's Hypothalamic Expression and Its Potential Relation to COVID-19-Associated Neurological Dysfunction

The coronavirus disease 2019 (COVID-19) pandemic has negatively impacted millions of lives, despite several vaccine interventions and strict precautionary measures. The main causative organism of this disease is the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) which infects the host via two key players: the angiotensin-converting enzyme 2 (ACE2) and the transmembrane protease, serine 2 (TMPRSS2). Some reports revealed that patients with glycemic dysregulation could have increased susceptibility to developing COVID-19 and its related neurological complications. However, no previous studies have looked at the involvement of these key molecules within the hypothalamus, which is the central regulator of glucose in the brain. By exposing embryonic mouse hypothalamic neurons to varying glucose concentrations, we aimed to investigate the expression of ACE2 and TMPRSS2 using quantitative real time polymerase chain reaction and western blotting. A significant and time-dependent increase and decrease was observed on the viability of hypothalamic neurons with increasing and decreasing glucose concentrations, respectively (p < 0.01 and p < 0.001, respectively). Under the same increasing and decreasing glucose conditions, the expression of hypothalamic ACE2 also revealed a significant and time-dependent increase (p < 0.01). These findings suggest that SARS-CoV-2 invades the hypothalamic circuitry. In addition, it highlights the importance of strict glycemic control for COVID-19 in diabetic patients.

RK-33, a small molecule inhibitor of host RNA helicase DDX3, suppresses multiple variants of SARS-CoV-2

SARS-CoV-2, the virus behind the deadly COVID-19 pandemic, continues to spread globally even as vaccine strategies are proving effective in preventing hospitalizations and deaths. However, evolving variants of the virus appear to be more transmissive and vaccine efficacy toward them is waning. As a result, SARS-CoV-2 will continue to have a deadly impact on public health into the foreseeable future. One strategy to bypass the continuing problem of newer variants is to target host proteins required for viral replication. We have used this host-targeted antiviral (HTA) strategy that targets DDX3X (DDX3), a host DEAD-box RNA helicase that is usurped by SARS-CoV-2 for virus production. We demonstrated that targeting DDX3 with RK-33, a small molecule inhibitor, reduced the viral load in four isolates of SARS-CoV-2 (Lineage A, and Lineage B Alpha, Beta, and Delta variants) by one to three log orders in Calu-3 cells. Furthermore, proteomics and RNA-seq analyses indicated that most SARS-CoV-2 genes were downregulated by RK-33 treatment. Also, we show that the use of RK-33 decreases TMPRSS2 expression, which may be due to DDX3s ability to unwind G-quadraplex structures present in the TMPRSS2 promoter. The data presented support the use of RK-33 as an HTA strategy to control SARS-CoV-2 infection, irrespective of its mutational status, in humans.

Unravelling the Mechanistic Role of ACE2 and TMPRSS2 in Hypertension: A Risk Factor for COVID-19

BACKGROUND

This review explores the mechanistic action of angiotensin-converting enzyme- 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) in the renin-angiotensinaldosterone system (RAAS) that predisposes hypertensive patients to the adverse outcome of severe COVID-19.

METHODS AND RESULTS

Entry of SARS-CoV-2 into the host cell via ACE2 disrupts the RAAS system, creating an imbalance between ACE and ACE2, with an increased inflammatory response, leading to hypertension (HTN), pulmonary vasoconstriction and acute respiratory distress. SARSCoV- 2 may also predispose infected individuals with existing HTN to a greater risk of severe COVID-19 complications. In the duality of COVID-19 and HTN, the imbalance of ACE and ACE2 results in an elevation of AngII and a decrease in Ang (1-7), a hyperinflammatory response and endothelial dysfunction. Endothelial dysfunction is the main factor predisposing hypertensive patients to severe COVID-19 and vice-versa.

CONCLUSION

Despite the increase in ACE2 expression in hypertensive SARS-CoV-2 infected patients, ARBs/ACE inhibitors do not influence their severity and clinical outcomes, implicating continued usage. Future large-scale clinical trials are warranted to further elucidate the association between HTN and SARS-CoV-2 infection and the use of ARBs/ACEIs in SARS-CoV-2 hypertensive patients.

Targeting autophagy regulation in NLRP3 inflammasome-mediated lung inflammation in COVID-19

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Emerging evidence indicates that the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome is activated, which results in a cytokine storm at the late stage of COVID-19. Autophagy regulation is involved in the infection and replication of SARS-CoV-2 at the early stage and the inhibition of NLRP3 inflammasome-mediated lung inflammation at the late stage of COVID-19. Here, we discuss the autophagy regulation at different stages of COVID-19. Specifically, we highlight the therapeutic potential of autophagy activators in COVID-19 by inhibiting the NLRP3 inflammasome, thereby avoiding the cytokine storm. We hope this review provides enlightenment for the use of autophagy activators targeting the inhibition of the NLRP3 inflammasome, specifically the combinational therapy of autophagy modulators with the inhibitors of the NLRP3 inflammasome, antiviral drugs, or anti-inflammatory drugs in the fight against COVID-19.

Exploring the phytochemicals of Platycodon grandiflorus for TMPRSS2 inhibition in the search for SARS-CoV-2 entry inhibitors

Platycodon grandiflorus (Jacq.) A. DC. (Campanulaceae) is commonly known as a balloon flower whose rhizomes have been widely utilized in traditional Chinese medicine (TCM) and in various Japanese prescriptions for the treatment of respiratory diseases, diabetes, and inflammatory disorders. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19) global pandemic requires priming of the virus's spike (S) protein by cleavage of the S proteins by a multi-domain type II transmembrane serine protease, transmembrane protease serine 2 (TMPRSS2) to gain entry into the host cell. The current research aims at the screening of active phytocompounds of P. grandiflorus as potential inhibitors of cellular TMPRSS2 using molecular docking and molecular dynamics simulations approach. In silico toxicity analyses show that out of a total of 34 phytocompounds selected for the study, 12 compounds obey Lipinski’s rule of five and have favourable pharmacokinetic properties. The top three lead molecules identified here were Apigenin, Luteolin and Ferulic acid which exhibited binding energies of −7.47 kcal/mol, −6.8 kcal/mol and −6.62 kcal/mol respectively with corresponding inhibition constants of 3.33 µM, 10.39 µM and 13.95 µM. The complexes between the lead molecules and the receptor were held by hydrogen bond interactions with key residues such as Gly383, Gly385, Glu389, Lys390, Asp435, Ser436, Ser441, Cys465 and Lys467, and hydrophobic interactions with surrounding residues. The stability of the protein–ligand complexes was evaluated during 100 ns molecular dynamics (MD) simulation by analysing key geometric properties such as RMSD, RMSF, radius of gyration, total solvent accessible surface area and the number of hydrogen bonds. The binding free energies analysis using MD simulations revealed that the compounds and TMPRSS2 have favourable thermodynamic interactions, which are primarily driven by van der Waals forces. As a result, the selected bioactive phytochemicals from P. grandiflorus that target the cellular TMPRSS2 could offer an alternative treatment option against SARS-CoV-2 infections.

Exercise-induced myokines downregulates the ACE2 level in bronchial epithelial cells: Implications for SARS-CoV-2 prevention

BACKGROUND

The Covid-19 pandemic has emerged as the leading public health challenge of our time (20th century). While vaccinations have finally blunted the death rate, concern has remained about more virulent forms highlighting the need for alternative approaches. Epidemiological studies indicate that physical activity has been shown to decrease the risk of infection of some respiratory viruses. Part of the salutary effects of exercise is believed to be through the elaboration of cytokines by contracting skeletal muscles (termed myokines). The objective of this study was to investigate whether exercise-induced myokines would mitigate the SARS-CoV-2 infectivity of the bronchial epithelium through modulating the SARS-CoV-2 Covid-19 receptor (angiotensin-converting enzyme 2 -ACE2) its priming enzyme, transmembrane serine protease 2 (TMPRSS2).

METHODS

We utilized a cell culture model of exercise to generate myokines by differentiating C2C12 cells into myotubules and inducing them to contract via low-frequency electric pulse stimulation. Condition media was concentrated via centrifugation and applied to human immortalized human bronchial epithelium cell line (6HBE14o) along with conditioned media from unstimulated myotubules as controls. Following exposure to myokines, the 16HBE14o cells were harvested and subjected to quantitative RT-PCR and Enzyme-Linked Immunosorbent Assay (ELISA) for assessment of mRNA and protein levels of ACE2 and TMPRSS2, respectively. Pilot proteomic data was performed with isotope barcoding and mass spectroscopy.

RESULTS

Quantitative Real-Time PCR of 16HBE14o with 48 h treated unstimulated vs. stimulated myokine treatment revealed a reduction of ACE2 and TMPRSS2 mRNA by 32% (p<2.69x10-5) and 41% (p<4.57x10-5), respectively. The high sensitivity of ELISAs showed downregulation of ACE2 and TMPRSS2 protein expression in 16HBE14o cells by 53% (p<0.01) and 32% (p<0.03) respectively with 48 h treated. For rigor, this work was replicated in the human lung cancer cell line A549, which mirrored the downregulation. Proteomic analysis showed dramatic alteration in myokine profile between contracted and uncontracted C2C12 tubules.

CONCLUSIONS

The current study explores a novel approach of a modified exercise cell culture system and uses ACE2 and TMPRSS2 as a surrogate marker of SARS-CoV-2 infectivity. In conclusion, we demonstrated biological data supporting exercise's protective effect against Covid-19. These further strengthen myokines' beneficial role as potential therapeutic targets against SARS-CoV-2 and similar viruses albeit these preliminary cell culture studies will require future validation in animal models.

Molecular Virology of SARS-CoV-2 and Related Coronaviruses

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The global COVID-19 pandemic continues to threaten the lives of hundreds of millions of people, with a severe negative impact on the global economy. Although several COVID-19 vaccines are currently being administered, none of them is 100% effective. Moreover, SARS-CoV-2 variants remain an important worldwide public health issue. Hence, the accelerated development of efficacious antiviral agents is urgently needed. Coronavirus depends on various host cell factors for replication. An ongoing research objective is the identification of host factors that could be exploited as targets for drugs and compounds effective against SARS-CoV-2. In the present review, we discuss the molecular mechanisms of SARS-CoV-2 and related coronaviruses, focusing on the host factors or pathways involved in SARS-CoV-2 replication that have been identified by genome-wide CRISPR screening.

Association of TMPRSS2 Gene Polymorphisms with COVID-19 Severity and Mortality: a Case-Control Study with Computational Analyses

Coronavirus disease 2019 (COVID-19) is a severe disease caused by a new variant of beta-coronavirus that first appeared in China. Human genetic factors, including polymorphisms, serve pivotal roles in the high transmission of SARS-CoV-2 and the stubbornly progressing sickness seen in a small but significant percentage of infected people; however, but these factors remain ill-defined. A total of 288 COVID-19 patients and 288 controls were genotyped for TMPRSS2 polymorphisms using both restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) and amplification refractory mutation system (ARMS)-PCR techniques. Different genotypes of TMPRSS2 polymorphisms were compared in terms of disease susceptibility and mortality. The statistical analysis showed that minor alleles of all studied variants statistically increased the risk of COVID-19, except for the rs75603675 C > A variant. The T allele of rs12329760 conferred an increased risk of COVID-19. Moreover, the AG/AC/TT/AG combination of genotypes significantly enhanced the risk of COVID-19 in our population. Different haplotypes of rs17854725/rs75603675/rs12329760/rs4303795 polymorphisms, including GACA, GACG, GATG, GATA, AATA, ACCG, ACTG, ACTA, GCCA, and GCTG, were found to be associated with increased risk of the disease (odds ratio > 1). Regarding the clinical and paraclinical characteristics, a statistically significant difference was found between non-severe and severe forms except for gender, platelet, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and underlying diseases. In addition, case genotypes of TMPRSS2 rs17854725 A > G, rs12329760 C > T, and rs4303795 A > G were significantly different regarding severe and non-severe forms of the disease (P-value < 0.001). Specifically, death was more frequent in carriers of the AG genotype of rs17854725 A > G (P-value = 0.022). Patients who carry the minor alleles of the four studied TMPRSS2 variants were rather vulnerable to COVID-19 infection. Our findings indicated that rs17854725 A > G (AA vs. AG and AA vs. GG), rs12329760 C > T (CC vs. CT and CC vs. TT), and rs4303795 A > G (AA vs. AG) genotypes of TMPRSS2 variations are associated with a more invasive disorder pattern. More studies on larger populations are needed to confirm our results.

Contribution of CD4+ T cell mediated inflammation to diarrhoea in patients with COVID-19

OBJECTIVES

This study aimed to explore the role of CD4+ T cells in the mechanisms of COVID-19 related diarrhoea.

METHODS

Lymphocyte subsets were analysed in COVID-19 patients, and the expression of angiotensin-converting enzyme 2 (ACE2), the transmembrane protease, serine 2 (TMPRSS2), and CD4+ T cell-related indicators in the colon were compared between patients with and without diarrhoea. Correlation analyses were performed for ACE2 and other indicators to identify the relationship between SARS-CoV-2 infection and CD4+ mediated inflammation. The expression and distribution of CD4+ T cell-associated chemokines and their receptors were detected to determine the possibility of migration of CD4+ T cells to inflammation sites.

RESULTS

The CD4+ T cell counts and percentages and CD4/CD8 ratio showed the most significant differences between the two groups. The diarrhoea group expressed higher levels of ACE2, Tbet, and TNFα at both the mRNA and protein levels, with no difference from the non-diarrhoea group for the percentage of ACE2+TNFα+ cells, indicating an indirect association between ACE2 and TNFα. The mRNA expression of CXCL10, CXCL11, and CXCR3, and the number of CD4+CXCR3+T cells was increased in the diarrhoea group.

CONCLUSIONS

CD4+ T cell-mediated inflammation may contribute to COVID-19 related diarrhoea. CXCR3+ mediated migration of CD4+ T cells into the gut may perpetuate inflammation.

Basic mechanisms of SARS-CoV-2 infection. What endocrine systems could be implicated?

Although SARS-CoV-2 viral attacks starts by the interaction of spike protein (S Protein) to ACE2 receptor located at the cell surface of respiratory tract and digestive system cells, different endocrine targets, endocrine organs and metabolic conditions are of fundamental relevance for understanding disease progression and special outcomes, in particular those of fatal consequences for the patient. During pandemic, moreover, a specific phenotype of COVID-19 metabolic patient has been described, characterized by being at particular risk of worse outcomes. In the present paper we describe the mechanism of viral interaction with endocrine organs, emphasizing the specific endocrine molecules of particular relevance explaining COVID-19 disease evolution and outcomes.

RK-33, a small molecule inhibitor of host RNA helicase DDX3, suppresses multiple variants of SARS-CoV-2

SARS-CoV-2, the virus behind the deadly COVID-19 pandemic, continues to spread globally even as vaccine strategies are proving effective in preventing hospitalizations and deaths. However, evolving variants of the virus appear to be more transmissive and vaccine efficacy towards them is waning. As a result, SARS-CoV-2 will continue to have a deadly impact on public health into the foreseeable future. One strategy to bypass the continuing problem of newer variants is to target host proteins required for viral replication. We have used this host-targeted antiviral (HTA) strategy that targets DDX3, a host DEAD-box RNA helicase that is usurped by SARS-CoV-2 for virus production. We demonstrated that targeting DDX3 with RK-33, a small molecule inhibitor, reduced the viral load in four isolates of SARS-CoV-2 (Lineage A, and Lineage B Alpha, Beta, and Delta variants) by one to three log orders in Calu-3 cells. Furthermore, proteomics and RNA-seq analyses indicated that most SARS-CoV-2 genes were downregulated by RK-33 treatment. Also, we show that the use of RK-33 decreases TMPRSS2 expression, which may be due to DDX3s ability to unwind G-quadraplex structures present in the TMPRSS2 promoter. The data presented supports the use of RK-33 as an HTA strategy to control SARS-CoV-2 infection, irrespective of its mutational status, in humans.

Immune response and potential therapeutic strategies for the SARS-CoV-2 associated with the COVID-19 pandemic

Following onset of the first recorded case of Coronavirus disease 2019 (COVID-19) in December 2019, more than 269 million cases and over 5.3 million deaths have been confirmed worldwide. COVID-19 is a highly infectious pneumonia, caused by a novel virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, it poses a severe threat to human health across the globe, a trend that is likely to persist in the foreseeable future. This paper reviews SARS-CoV-2 immunity, the latest development of anti-SARS-CoV-2 drugs as well as exploring in detail, immune escape induced by SARS-CoV-2. We expect that the findings will provide a basis for COVID-19 prevention and treatment.