SARS-CoV-2 N Protein Induces Acute Kidney Injury via Smad3-Dependent G1 Cell Cycle Arrest Mechanism

Trilobolide-6-O-isobutyrate exerts anti-tumor effects on cholangiocarcinoma cells through inhibiting JAK/STAT3 signaling pathway

Trilobolide-6-O-isobutyrate exhibits significant antitumor effects on cholangiocarcinoma (CCA) cells by effectively inhibiting the JAK/STAT3 signaling pathway. This study aims to investigate the mechanisms underlying the antitumor properties of trilobolide-6-O-isobutyrate, and to explore its potential as a therapeutic agent for CCA. This study illustrates that trilobolide-6-O-isobutyrate efficiently suppresses CCA cell proliferation in a dose- and time-dependent manner. Furthermore, trilobolide-6-O-isobutyrate stimulates the production of reactive oxygen species, leading to oxidative stress and initiation of apoptosis via the activation of the mitochondrial pathway. Data from xenograft tumor assays in nude mice confirms that TBB inhibits tumor growth, and that there are no obvious toxic effects or side effects in vivo. Mechanistically, trilobolide-6-O-isobutyrate exerts antitumor effects by inhibiting STAT3 transcriptional activation, reducing PCNA and Bcl-2 expression, and increasing P21 expression. These findings emphasizes the potential of trilobolide-6-O-isobutyrate as a promising therapeutic candidate for the treatment of CCA.

Immunological mechanisms of the nucleocapsid protein in COVID-19

The emergence of corona virus disease 2019 (COVID-19), resulting from Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has left an indelible mark on a global scale, causing countless infections and fatalities. This investigation delves into the role of the SARS-CoV-2 nucleocapsid (N) protein within the HEK293 cells, shedding light on its influence over apoptosis, interferon signaling, and cytokines production. The N gene was amplified, inserted into the pAdTrack-CMV vector, and then transfected to the HEK293 cells. Changes in the expression of IRF3, IRF7, IFN-β, BAK, BAX, and BCL-2 genes were evaluated. The levels of proinflammatory cytokines of IL-6, IL-12, IL-1β, and TNF-α were also determined. The N protein exhibited an anti-apoptotic effect by modulating critical genes associated with apoptosis, including BAK, BAX, and BCL-2. This effect potentially prolonged the survival of infected cells. The N protein also played a role in immune evasion by suppressing the interferon pathway, evidenced by the downregulation of essential interferon regulatory factors of IRF3 and IRF7, and IFN-β expression. The N protein expression led to a substantial increase in the production of proinflammatory cytokines of IL-6, IL-12, IL-1β, and TNF-α. The N protein emerged as a versatile factor and was exerted over apoptosis, interferon signaling, and cytokine production. These findings carry potential implications for the development of targeted therapies to combat COVID-19 and mitigate its global health impact.

Artesunate-Nanoliposome-TPP, a Novel Drug Delivery System That Targets the Mitochondria, Attenuates Cisplatin-Induced Acute Kidney Injury by Suppressing Oxidative Stress and Inflammatory Effects

Background

Acute kidney injury (AKI) is a syndrome, posing a substantial healthcare burden. The pathological basis of AKI is associated with inflammation and oxidative stress which cause additional damage to mitochondria. Artesunate (ATS) is a derivative of artemisinin isolated from Artemisia annua L. that is an effective treatment for malaria and favored for the prevention and treatment of kidney diseases. However, there are still challenges related to its efficacy, including poor water solubility, limited oral bioavailability and short half-life. Liposome-based nanoparticles are used for drug delivery due to their ideal biocompatibility and their ability to improve the bioavailability of specific drugs and enhance drug efficacy.

Methods

In this study, a novel TPP-based natural ATS-nanoliposome, namely T-A-Ls, was applied for the treatment of AKI. ATS was encapsulated with or without triphenylphosphonium (TPP)-modified nanoliposomes. AKI was induced by cisplatin in C57BL/6J mice and a cisplatin-induced injury model was generated in HK-2 cells in vitro. Blood urea nitrogen (BUN), serum creatinine (Scr) measurements and section staining were utilized to assess renal protective effect of T-A-Ls. Inflammatory-related factors and proteins were quantified via Elisa, Immunofluorescence and Western Blot (WB). The anti-mitochondrial oxidative stress effect of T-A-Ls was determined by ROS, JC-1 and oxygen consumption rate (OCR) kits. Immunohistochemistry and WB were conducted to measure associated protein expressions. In vivo biodistribution and the concentration of T-A-Ls in kidney were also explored.

Results

T-A-Ls exhibited good oxidative resistance, preferential renal uptake, mitochondrial targeting, and it ameliorated kidney injury in cisplatin-induced AKI mice. Mitochondrial dysfunction, ATP production and respiratory capacity were improved in damaged HK-2 cells; ROS content decreased while mitochondrial membrane potential recovered. T-A-Ls exerted renal protection by inhibiting inflammation and reducing oxidative stress; these effects were mediated by a downregulation in the expression of RAGE and iNOS and an upregulation in both Nrf2 and HO-1.

Conclusion

T-A-Ls could improve the delivery of ATS to the kidney, offering a promising avenue to treat AKI.

Klotho-derived peptide KP1 ameliorates SARS-CoV-2-associated acute kidney injury

Introduction: The severe cases of COVID-19, a disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), often present with acute kidney injury (AKI). Although old age and preexisting medical conditions have been identified as principal risk factors for COVID-19-associated AKI, the molecular basis behind such a connection remains unknown. In this study, we investigated the pathogenic role of Klotho deficiency in COVID-19-associated AKI and explored the therapeutic potential of Klotho-derived peptide 1 (KP1). Methods: We assessed the susceptibility of Klotho deficient Kl/Kl mice to developing AKI after expression of SARS-CoV-2 N protein. The role of KP1 in ameliorating tubular injury was investigated by using cultured proximal tubular cells (HK-2) in vitro and mouse model of ischemia-reperfusion injury (IRI) in vivo. Results: Renal Klotho expression was markedly downregulated in various chronic kidney disease (CKD) models and in aged mice. Compared to wild-type counterparts, mutant KL/KL mice were susceptible to overexpression of SARS-CoV-2 N protein and developed kidney lesions resembling AKI. In vitro, expression of N protein alone induced HK-2 cells to express markers of tubular injury, cellular senescence, apoptosis and epithelial-mesenchymal transition, whereas both KP1 and Klotho abolished these lesions. Furthermore, KP1 mitigated kidney dysfunction, alleviated tubular injury and inhibited apoptosis in AKI model induced by IRI and N protein. Conclusion: These findings suggest that Klotho deficiency is a key determinant of developing COVID-19-associated AKI. As such, KP1, a small peptide recapitulating Klotho function, could be an effective therapeutic for alleviating AKI in COVID-19 patients.

One master and two servants: One Zr(Ⅳ) with two ligands of TCPP and NH2-BDC form the MOF as the electrochemiluminescence emitter for the biosensing application

Here we put forward an innovative "one master and two servants" strategy for enhancing the ECL performance. A novel ECL luminophore named Zr-TCPP/NH2-BDC (TCPP@UiO-66-NH2) was synthesized by self-assembly of meso-tetra(4-carboxyphenyl)porphine (TCPP) and 4-aminobenzoic acid (NH2-BDC) with Zr clusters. TCPP@UiO-66-NH2 has a porous structure and a highly ordered structure, which allows the molecular motion of TCPP to be effectively confined, thereby inhibiting nonradiative energy transfer. Importantly, TCPP@UiO-66-NH2 has a higher and more stable ECL signal. To further improve the sensitivity of the sensor, we use polydopamine-coated manganese dioxide (PDA@MnO2), which has a double quenching effect, as the quencher. The nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2-N) is one of the ideal markers for the early diagnosis of COVID-19, and its sensitivity detection is of great significance for the prevention and treatment of COVID-19. Thus, we constructed a quenching-type ECL sensor for the ultrasensitive detection of the SARS-CoV-2-N. Its linear range is 10 fg/mL∼1 μg/mL and the calculated detection limit is 1.4 fg/mL (S/N = 3). The spiked recoveries are 97.40-103.8%, with the relative standard deviations (RSD) under 3.0%. More importantly, the technique offers a viable way to identify and diagnose viral infections early.

Epidemiological and clinical features of SARS-CoV-2 Omicron variant infection in Quanzhou, Fujian province: a retrospective study

Epidemiological and clinical data of patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant (BA.2) admitted to three designated hospitals in Quanzhou City, Fujian Province, China, were collected and analyzed. Overall, 2,541 patients infected with BA.2, comprising 1,060 asymptomatic, 1,287 mild, and 194 moderate infections, were enrolled. The percentage of moderate infections was higher in patients aged ≥ 60 years than in those aged < 18 years and 18-59 years. The median hospitalization duration was 17 days. Among the 2,541 patients, 43.52% had a clear history of close contact. The vaccination rate was 87.92%, and the percentage of asymptomatic infections was higher in vaccinated than in unvaccinated patients. Moreover, patients with underlying diseases, including hypertension and diabetes mellitus, had more moderate infections than those without underlying diseases. The three most common clinical manifestations were fever, dry cough, and sore throat. The albumin-to-globulin (A/G) ratio and lymphocyte count decreased in cases with mild and moderate infections, while procalcitonin, erythrocyte sedimentation rate, interleukin-6, D-dimer, and C4 levels increased. Advanced age, non-vaccination, and underlying comorbid diseases were high-risk factors for disease progression in patients. However, dynamic monitoring of blood routine parameters, A/G ratio, and inflammatory indicators facilitated the prediction of disease progression.

The role of SARS-CoV-2 nucleocapsid protein in antiviral immunity and vaccine development

ABSTRACTThe coronavirus disease 2019 (COVID-19) has caused enormous health risks and global economic disruption. This disease is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 nucleocapsid protein is a structural protein involved in viral replication and assembly. There is accumulating evidence indicating that the nucleocapsid protein is multi-functional, playing a key role in the pathogenesis of COVID-19 and antiviral immunity against SARS-CoV-2. Here, we summarize its potential application in the prevention of COVID-19, which is based on its role in inflammation, cell death, antiviral innate immunity, and antiviral adaptive immunity.

SARS-CoV-2 N protein induced acute kidney injury in diabetic db/db mice is associated with a Mincle-dependent M1 macrophage activation

"Cytokine storm" is common in critically ill COVID-19 patients, however, mechanisms remain largely unknown. Here, we reported that overexpression of SARS-CoV-2 N protein in diabetic db/db mice significantly increased tubular death and the release of HMGB1, one of the damage-associated molecular patterns (DAMPs), to trigger M1 proinflammatory macrophage activation and production of IL-6, TNF-α, and MCP-1 via a Mincle-Syk/NF-κB-dependent mechanism. This was further confirmed in vitro that overexpression of SARS-CoV-2 N protein caused the release of HMGB1 from injured tubular cells under high AGE conditions, which resulted in M1 macrophage activation and production of proinflammatory cytokines via a Mincle-Syk/NF-κB-dependent mechanism. This was further evidenced by specifically silencing macrophage Mincle to block HMGB1-induced M1 macrophage activation and production of IL-6, TNF-α, and MCP-1 in vitro. Importantly, we also uncovered that treatment with quercetin largely improved SARS-CoV-2 N protein-induced AKI in db/db mice. Mechanistically, we found that quercetin treatment significantly inhibited the release of a DAMP molecule HMGB1 and inactivated M1 pro-inflammatory macrophage while promoting reparative M2 macrophage responses by suppressing Mincle-Syk/NF-κB signaling in vivo and in vitro. In conclusion, SARS-CoV-2 N protein-induced AKI in db/db mice is associated with Mincle-dependent M1 macrophage activation. Inhibition of this pathway may be a mechanism through which quercetin inhibits COVID-19-associated AKI.

RAGE Is a Receptor for SARS-CoV-2 N Protein and Mediates N Protein-induced Acute Lung Injury

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (N-protein) increases early in body fluids during infection and has recently been identified as a direct inducer for lung injury. However, the signal mechanism of N-protein in the lung inflammatory response remains poorly understood. The goal of this study was to determine whether RAGE (receptor for advanced glycation endproducts) participated in N-protein-induced acute lung injury. The binding between N-protein and RAGE was examined via assays for protein-protein interaction. To determine the signaling mechanism in vitro, cells were treated with recombinant N-protein and assayed for the activation of the RAGE/MAPK (mitogen-activated protein kinase)/NF-ĸB pathway. RAGE deficiency mice and antagonist were used to study N-protein-induced acute lung injury in vivo. Binding between N-protein and RAGE was confirmed via flow cytometry-based binding assay, surface plasmon resonance, and ELISA. Pull-down and coimmunoprecipitation assays revealed that N-protein bound RAGE via both N-terminal and C-terminal domains. In vitro, N-protein activated the RAGE-ERK1/2-NF-ĸB signaling pathway and induced a proinflammatory response. RAGE deficiency subdued N-protein-induced proinflammatory signaling and response. In vivo, RAGE was upregulated in the BAL and lung tissue after recombinant N-protein insult. RAGE deficiency and small molecule antagonist partially protected mice from N-protein-induced acute lung injury. Our study demonstrated that RAGE is a receptor for N-protein. RAGE is partially responsible for N-protein-induced acute lung injury and has the potential to become a therapeutic target for treating coronavirus disease.

SARS-CoV-2 and the DNA damage response

The recent coronavirus disease 2019 (COVID-19) pandemic was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 is characterized by respiratory distress, multiorgan dysfunction and, in some cases, death. The virus is also responsible for post-COVID-19 condition (commonly referred to as 'long COVID'). SARS-CoV-2 is a single-stranded, positive-sense RNA virus with a genome of approximately 30 kb, which encodes 26 proteins. It has been reported to affect multiple pathways in infected cells, resulting, in many cases, in the induction of a 'cytokine storm' and cellular senescence. Perhaps because it is an RNA virus, replicating largely in the cytoplasm, the effect of SARS-Cov-2 on genome stability and DNA damage responses (DDRs) has received relatively little attention. However, it is now becoming clear that the virus causes damage to cellular DNA, as shown by the presence of micronuclei, DNA repair foci and increased comet tails in infected cells. This review considers recent evidence indicating how SARS-CoV-2 causes genome instability, deregulates the cell cycle and targets specific components of DDR pathways. The significance of the virus's ability to cause cellular senescence is also considered, as are the implications of genome instability for patients suffering from long COVID.

COVID-19 and Kidney: The Importance of Follow-Up and Long-Term Screening

Renal involvement and kidney injury are common in COVID-19 patients, and the symptoms are more severe if the patient already has renal impairment. Renal involvement in COVID-19 is multifactorial, and the renal tubule is mainly affected, along with podocyte injury during SARS-CoV-2 infection. Inflammation, complement activation, hypercoagulation, and crosstalk between the kidney and lungs, brain, and heart are contributory factors. Kidney injury during the acute phase, termed acute kidney injury (AKI), may proceed to chronic kidney disease if the patient is discharged with renal impairment. Both AKI and chronic kidney disease (CKD) increase mortality in COVID-19 patients. Further, COVID-19 infection in patients suffering from CKD is more severe and increases the mortality rate. Thus, it is important to address both categories of patients, either developing AKI or CKD after COVID-19 or previously having CKD, with proper management and treatment. This review discusses the pathophysiology involved in AKI and CKD in COVID-19 infection, followed by management and treatment of AKI and CKD. This is followed by a discussion of the importance of screening and treatment of CKD patients infected with COVID-19 and future perspectives to improve treatment in such patients.

Serum TGF-β as a predictive biomarker for severe disease and fatality of COVID-19

For targeted intervention in coronavirus disease 2019 (COVID-19), there is a high medical need for biomarkers that predict disease progression and severity in the first days after symptom onset. This study assessed the utility of early transforming growth factor β (TGF-β) serum levels in COVID-19 patients to predict disease severity, fatality, and response to dexamethasone therapy. Patients with severe COVID-19 had significantly higher TGF-β levels (416 pg/mL) as compared to patients with mild (165 pg/mL, p < 0.0001) or moderate COVID-19 (241 pg/mL; p < 0.0001). Receiver operating characteristics area under the curve values were 0.92 (95% confidence interval [CI] 0.85-0.99, cut-off: 255 pg/mL) for mild versus severe COVID-19, and 0.83 (95% CI 0.65-1.0, cut-off: 202 pg/mL) for moderate versus severe COVID-19. Patients who died of severe COVID-19 had significantly higher TGF-β levels (453 pg/mL) as compared to convalescent patients (344 pg/mL), and TGF-β levels predicted fatality (area under the curve: 0.75, 95% CI 0.53-0.96). TGF-β was significantly reduced in severely ill patients treated with dexamethasone (301 pg/mL) as compared to untreated patients (416 pg/mL; p < 0.05). Early TGF-β serum levels in COVID-19 patients predict, with high accuracy, disease severity, and fatality. In addition, TGF-β serves as a specific biomarker to assess response to dexamethasone treatment.

Omics data analysis reveals common molecular basis of small cell lung cancer and COVID-19

The impact of COVID-19 infection on individuals with small cell lung cancer (SCLC) poses a serious threat. Unfortunately, the molecular basis of this severe comorbidity has yet to be elucidated. The present study addresses this gap utilizing publicly available omics data of COVID-19 and SCLC to explore the key molecules and associated pathways involved in the convergence of these diseases. Findings revealed 402 genes, that exhibited differential expression patterns in SCLC patients and also play a pivotal role in COVID-19 pathogenesis. Subsequent functional enrichment analyses identified relevant ontologies and pathways that are significantly associated with these genes, revealing important insights into their potential biological, molecular and cellular functions. The protein-protein interaction network, constructed under four combinatorial topological assessments, highlighted SMAD3, CAV1, PIK3R1, and FN1 as the primary components to this comorbidity. Our results suggest that these components significantly regulate this cross-talk triggering the PI3K-AKT and TGF-β signaling pathways. Lastly, this study made a multi-step computational attempt and identified corylifol A and ginkgetin from natural sources that can potentially inhibit these components. Therefore, the outcomes of this study offer novel perspectives on the common molecular mechanisms underlying SCLC and COVID-19 and present future opportunities for drug development.Communicated by Ramaswamy H. Sarma.

In Memory of the Virologist Jianguo Wu, 1957-2022

It is with deep sorrow that we mourn the passing of the virologist Professor Jianguo Wu [...].

A Tribute to Professor Jianguo Wu

It has been a couple of months since Professor Jianguo Wu left us [...].

Paxlovid for hospitalized COVID-19 patients with chronic kidney disease

BACKGROUND

COVID-19 causes significant mortality during the recent pandemic. Data regarding the effectiveness of Paxlovid on COVID-19 patients with chronic kidney disease (CKD, eGFR <90 ml/min) are limited.

METHODS

A retrospective cohort study was performed on the clinical data of the hospitalized adult patients with confirmed COVID-19 infection collected at Renji Hospital from April 7, 2022 to June 21, 2022. The association of Paxlovid treatment with early (within 5 days post diagnosis) or late (5 days or later post diagnosis) initiation time with clinical outcomes was assessed by Cox proportional hazards regression model with time-dependent covariates.

RESULT

1279 of 2387 enrollees were included in the study. Patients with early initiation of Paxlovid had a lower all-cause death rate compared to those with late initiation or without Paxlovid treatment (P = 0.046). For the CKD patients with Charlson comorbidity index (CCI) > 7, the early initiation of Paxlovid was associated with a lower all-cause death rate compared to the later initiation or the lack of Paxlovid treatment (P = 0.041). Cox regression analyses revealed that eGFR (HR 4.21 [95%, CI 1.62-10.99]), Paxlovid treatment (0.32 [0.13-0.77]), CCI (4.32 [1.64-11.40]), ICU admission (2.65 [1.09-6.49]), hsCRP (3.88 [1.46-7.80]), chronic liver disease (4.02 [1.09-14.85]) were the independent risk factors for all-cause death for CKD patients after adjusting for demographics and biochemical indexes.

CONCLUSIONS

All-cause death, invasive ventilation, and ICU admission were all significantly lowered by an early initiation of Paxlovid treatment in COVID-19 patients with severe CKD.

In silico evidence implicating novel mechanisms of Prunella vulgaris L. as a potential botanical drug against COVID-19-associated acute kidney injury

COVID-19-associated acute kidney injury (COVID-19 AKI) is an independent risk factor for in-hospital mortality and has the potential to progress to chronic kidney disease. Prunella vulgaris L., a traditional Chinese herb that has been used for the treatment of a variety of kidney diseases for centuries, could have the potential to treat this complication. In this study, we studied the potential protective role of Prunella vulgaris in COVID-19 AKI and explored its specific mechanisms applied by network pharmacology and bioinformatics methods. The combination of the protein-protein interaction network and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment -target gene network revealed eight key target genes (VEGFA, ICAM1, IL6, CXCL8, IL1B, CCL2, IL10 and RELA). Molecular docking showed that all these eight gene-encoded proteins could be effectively bound to three major active compounds (quercetin, luteolin and kaempferol), thus becoming potential therapeutic targets. Molecular dynamics simulation also supports the binding stability of RELA-encoded protein with quercetin and luteolin. Together, our data suggest that IL6, VEGFA, and RELA could be the potential drug targets by inhibiting the NF-κB signaling pathway. Our in silico studies shed new insights into P. vulgaris and its ingredients, e.g., quercetin, as potential botanical drugs against COVID-19 AKI, and warrant further studies on efficacy and mechanisms.

SARS-CoV-2 N protein enhances the anti-apoptotic activity of MCL-1 to promote viral replication

Viral infection in respiratory tract usually leads to cell death, impairing respiratory function to cause severe disease. However, the diversity of clinical manifestations of SARS-CoV-2 infection increases the complexity and difficulty of viral infection prevention, and especially the high-frequency asymptomatic infection increases the risk of virus transmission. Studying how SARS-CoV-2 affects apoptotic pathway may help to understand the pathological process of its infection. Here, we uncovered SARS-CoV-2 imployed a distinct anti-apoptotic mechanism via its N protein. We found SARS-CoV-2 virus-like particles (trVLP) suppressed cell apoptosis, but the trVLP lacking N protein didn't. Further study verified that N protein repressed cell apoptosis in cultured cells, human lung organoids and mice. Mechanistically, N protein specifically interacted with anti-apoptotic protein MCL-1, and recruited a deubiquitinating enzyme USP15 to remove the K63-linked ubiquitination of MCL-1, which stabilized this protein and promoted it to hijack Bak in mitochondria. Importantly, N protein promoted the replications of IAV, DENV and ZIKV, and exacerbated death of IAV-infected mice, all of which could be blocked by a MCL-1 specific inhibitor, S63845. Altogether, we identifed a distinct anti-apoptotic function of the N protein, through which it promoted viral replication. These may explain how SARS-CoV-2 effectively replicates in asymptomatic individuals without cuasing respiratory dysfunction, and indicate a risk of enhanced coinfection with other viruses. We anticipate that abrogating the N/MCL-1-dominated apoptosis repression is conducive to the treatments of SARS-CoV-2 infection as well as coinfections with other viruses.

Evaluation of the interaction between tumor growth factor-β and interferon type I pathways in patients with COVID-19: focusing on ages 1 to 90 years

BACKGROUND

Evidence revealed that age could affect immune responses in patients with the acute respiratory syndrome of coronavirus 2 (SARS-CoV-2) infection. This study investigated the impact of age on immune responses, especially on the interaction between the tumor growth factor-β (TGF-β) and interferon type-I (IFN-I) axes in the pathogenesis of novel coronavirus disease 2019 (COVID-19).

METHODS

This age-matched case-control investigation enrolled 41 COVID-19 patients and 40 healthy controls categorized into four groups, including group 1 (up to 20 years), group 2 (20-40 years), group 3 (40-60 years), and group 4 (over 60 years). Blood samples were collected at the time of admission. The expression of TGF-βRI, TGF-βRII, IFNARI, IFNARII, interferon regulatory factor 9 (IRF9), and SMAD family member 3 (SMAD3) was measured using the real-time PCR technique. In addition, serum levels of TGF-β, IFN-α, and SERPINE1 were measured by the enzyme-linked immunosorbent assay (ELISA) technique. All biomarkers were measured and analyzed in the four age studies groups.

RESULTS

The expression of TGF-βRI, TGF-βRII, IFNARI, IFNARII, IRF9, and SMAD3 was markedly upregulated in all age groups of patients compared with the matched control groups. Serum levels of IFN-α and SERPINE1 were significantly higher in patient groups than in control groups. While TGF-β serum levels were only significantly elevated in the 20 to 40 and over 60 years patient group than in matched control groups.

CONCLUSIONS

These data showed that the age of patients, at least at the time of admission, may not significantly affect TGF-β- and IFN-I-associated immune responses. However, it is possible that the severity of the disease affects these pathway-mediated responses, and more studies with a larger sample size are needed to verify it.

Efficient Targeted Delivery of Bifunctional Circular Aptamer-ASO Chimera to Suppress the SARS-CoV-2 Proliferation and Inflammation

Inhibition of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and excessive inflammation is the current task in the prevention and treatment of corona vireus disease 2019 (COVID-19). Here, a dual-function circular aptamer-ASO chimera (circSApt-NASO) is designed to suppress SARS-CoV-2 replication and inflammation. The chemically unmodified circSApt-NASO exhibits high serum stability by artificial cyclization. It is also demonstrated that the SApt binding to spike protein enables the chimera to be efficiently delivered into the host cells expressing ACE2 along with the infection of SARS-CoV-2. Among them, the SApt potently inhibits spike-induced inflammation. The NASO targeting to silence N genes not only display robust anti-N-induced inflammatory activity, but also achieve efficient inhibition of SARS-CoV-2 replication. Overall, benefiting from the high stability of the cyclization, antispike aptamer-dependent, and viral infection-mediate targeted delivery, the circSApt-NASO displays robust potential against authentic SARS-CoV-2 and Omicron, providing a promising specific anti-inflammatory and antiproliferative reagent for therapeutic COVID-19.

Roles of p53-Mediated Host–Virus Interaction in Coronavirus Infection

The emergence of the SARS-CoV-2 coronavirus has garnered global attention due to its highly pathogenic nature and the resulting health crisis and economic burden. Although drugs such as Remdesivir have been considered a potential cure by targeting the virus on its RNA polymerase, the high mutation rate and unique 3’ to 5’ exonuclease with proofreading function make it challenging to develop effective anti-coronavirus drugs. As a result, there is an increasing focus on host–virus interactions because coronaviruses trigger stress responses, cell cycle changes, apoptosis, autophagy, and the dysregulation of immune function and inflammation in host cells. The p53 tumor suppressor molecule is a critical regulator of cell signaling pathways, cellular stress responses, DNA repair, and apoptosis. However, viruses can activate or inhibit p53 during viral infections to enhance viral replication and spread. Given its pivotal role in cell physiology, p53 represents a potential target for anti-coronavirus drugs. This review aims to summarize the relationship between p53 and coronaviruses from various perspectives, to shed light on potential targets for antiviral drug development and vaccine design.

SARS-CoV-2 viral protein ORF3A injures renal tubules by interacting with TRIM59 to induce STAT3 activation

Acute kidney injury occurs frequently in COVID-19 patients infected by the coronavirus SARS-CoV-2, and infection of kidney cells by this virus has been reported. However, little is known about the direct impact of the SARS-CoV-2 infection upon the renal tubular cells. We report that SARS-CoV-2 activated signal transducer and activator of transcription 3 (STAT3) signaling and caused cellular injury in the human renal tubular cell line. Mechanistically, the viral protein ORF3A of SARS-CoV-2 augmented both NF-κB and STAT3 signaling and increased the expression of kidney injury molecule 1. SARS-CoV-2 infection or expression of ORF3A alone elevated the protein level of tripartite motif-containing protein 59 (TRIM59), an E3 ubiquitin ligase, which interacts with both ORF3A and STAT3. The excessive TRIM59 in turn dissociated the phosphatase TCPTP from binding to STAT3 and hence inhibited the dephosphorylation of STAT3, leading to persistent STAT3 activation. Consistently, ORF3A induced renal injury in zebrafish and mice. In addition, expression of TRIM59 was elevated in the kidney autopsies of COVID-19 patients with acute kidney injury. Thus, the aberrant activation of STAT3 signaling by TRIM59 plays a significant role in the renal tubular cell injury caused by SARS-CoV-2, which suggests a potential targeted therapy for the renal complications of COVID-19.

Treatment with quercetin inhibits SARS-CoV-2 N protein-induced acute kidney injury by blocking Smad3-dependent G1 cell-cycle arrest

Increasing evidence shows that SARS-CoV-2 can infect kidneys and cause acute kidney injury (AKI) in critically ill COVID-19 patients. However, mechanisms through which COVID-19 induces AKI are largely unknown, and treatment remains ineffective. Here, we report that kidney-specific overexpressing SARS-CoV-2 N gene can cause AKI, including tubular necrosis and elevated levels of serum creatinine and BUN in 8-week-old diabetic db/db mice, which become worse in those with older age (16 weeks) and underlying diabetic kidney disease (DKD). Treatment with quercetin, a purified product from traditional Chinese medicine (TCM) that shows effective treatment of COVID-19 patients, can significantly inhibit SARS-CoV-2 N protein-induced AKI in diabetic mice with or without underlying DKD. Mechanistically, quercetin can block the binding of SARS-CoV-2 N protein to Smad3, thereby inhibiting Smad3 signaling and Smad3-mediated cell death via the p16-dependent G1 cell-cycle arrest mechanism in vivo and in vitro. In conclusion, SARS-CoV-2 N protein is pathogenic and can cause severe AKI in diabetic mice, particularly in those with older age and pre-existing DKD, via the Smad3-dependent G1 cell-cycle arrest mechanism. Importantly, we identify that quercetin may be an effective TCM compound capable of inhibiting COVID-19 AKI by blocking SARS-CoV-2 N-Smad3-mediated cell death pathway.

SARS-CoV-2 N protein mediates intercellular nucleic acid dispersion, a feature reduced in Omicron

The coronavirus nucleocapsid (N) protein is known to bind to nucleic acids and facilitate viral genome encapsulation. Here we report that the N protein can mediate RNA or DNA entering neighboring cells through ACE2-independent, receptor (STEAP2)-mediated endocytosis, and achieve gene expression. The effect is more pronounced for the N protein of wild-type SARS-CoV-2 than that of the Omicron variant and other human coronaviruses. This effect is enhanced by RANTES (CCL5), a chemokine induced by N protein, and lactate, a metabolite produced in hypoxia, to cause more damage. These findings might explain the clinical observations in SARS-CoV-2-infected cases. Moreover, the N protein-mediated function can be inhibited by N protein-specific monoclonal antibodies or p38 mitogen-activated protein kinase inhibitors. Since the N-protein-mediated nucleic acid endocytosis involves a receptor commonly expressed in many types of cells, our findings suggest that N protein may have an additional role in SARS-CoV-2 pathogenesis.

SARS-CoV-2 N Protein Triggers Acute Lung Injury via Modulating Macrophage Activation and Infiltration in in vitro and in vivo

Background

SARS-CoV-2-induced acute lung injury but its nucleocapsid (N) and/or Spike (S) protein involvements in the disease pathology remain elusive.

Methods

In vitro, the cultured THP-1 macrophages were stimulated with alive SARS-CoV-2 virus at different loading dose, N protein or S protein with/without TICAM2-siRNA, TIRAP-siRNA or MyD88-siRNA. The TICAM2, TIRAP and MyD88 expression in the THP-1 cells after N protein stimulation were determined. In vivo, naïve mice or mice with depletion macrophages were injected with N protein or dead SARS-CoV-2. The macrophages in the lung were analyzed with flow cytometry, and lung sections were stained with H&E or immunohistochemistry. Culture supernatants and serum were harvested for cytokines measurements with cytometric bead array.

Results

Alive SARS-CoV-2 virus or N protein but not S protein induced high cytokine releases from macrophages in a time or virus loading dependent manner. MyD88 and TIRAP but not TICAM2 were highly involved in macrophage activation triggered by N protein whilst both inhibited with siRNA decreased inflammatory responses. Moreover, N protein and dead SARS-CoV-2 caused systemic inflammation, macrophage accumulation and acute lung injury in mice. Macrophage depletion in mice decreased cytokines in response to N protein.

Conclusion

SARS-CoV-2 and its N protein but not S protein induced acute lung injury and systemic inflammation, which was closely related to macrophage activation, infiltration and release cytokines.

Highly pathogenic coronaviruses and the kidney

Since the end of 2019, the outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has triggered a pneumonia epidemic, posing a significant public health challenge in 236 countries, territories, and regions worldwide. Clinically, in addition to the symptoms of pulmonary infection, many patients with SARS-CoV-2 infections, especially those with a critical illness, eventually develop multiple organ failure in which damage to the kidney function is common, ultimately leading to severe consequences such as increased mortality and morbidity. To date, three coronaviruses have set off major global public health security incidents: Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and SARS-CoV-2. Among the diseases caused by the coronaviruses, the coronavirus disease 2019 (COVID-19) has been the most impactful and harmful. Similar to with SARS-CoV-2 infections, previous studies have shown that kidney injury is also common and prominent in patients with the two other highly pathogenic coronaviruses. Therefore, in this review, we aimed to comprehensively summarize the epidemiological and clinical characteristics of these three pandemic-level infections, provide a deep analysis of the potential mechanism of COVID-19 in various types of kidney diseases, and explore the causes of secondary kidney diseases of SARS-CoV-2, so as to provide a reference for further research and the clinical prevention of kidney damage caused by coronaviruses.

Research and development of Chinese anti-COVID-19 drugs

The outbreak and spread of coronavirus disease 2019 (COVID-19) highlighted the importance and urgency of the research and development of therapeutic drugs. Very early into the COVID-19 pandemic, China has begun developing drugs, with some notable progress. Herein, we summarizes the anti-COVID-19 drugs and promising drug candidates originally developed and researched in China. Furthermore, we discussed the developmental prospects, mechanisms of action, and advantages and disadvantages of the anti-COVID-19 drugs in development, with the aim to contribute to the rational use of drugs in COVID-19 treatment and more effective development of new drugs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the variants. Neutralizing antibody is an effective approach to overcome COVID-19. However, drug resistance induced by rapid virus mutation will likely to challenge neutralizing antibodies. Taking into account current epidemic trends, small molecule drugs have a crucial role in fighting COVID-19 due to their significant advantage of convenient administration and affordable and broad-spectrum. Traditional Chinese medicines, including natural products and traditional Chinese medicine prescriptions, contribute to the treatment of COVID-19 due to their unique mechanism of action. Currently, the research and development of Chinese anti-COVID-19 drugs have led to some promising achievements, thus prompting us to expect even more rapidly available solutions.

Immune-profiling of SARS-CoV-2 viremic patients reveals dysregulated innate immune responses

SARS-CoV-2 plasma viremia has been associated with severe disease and death in COVID-19. However, the effects of viremia on immune responses in blood cells remain unclear. The current study comprehensively examined transcriptional signatures of PBMCs involving T cells, B cells, NK cells, monocytes, myeloid dendritic cells (mDCs), and plasmacytoid dendritic cells (pDCs) respectively, from three different groups including individuals with moderate (nM), or severe disease with (vS) or without (nS) detectable plasma viral load. Whole transcriptome analysis demonstrated that all seven immune cell subsets were associated with disease severity regardless of cell type. Supervised clustering analysis demonstrated that mDCs and pDCs gene signatures could distinguish disease severity. Notably, transcriptional signatures of the vS group were enriched in pathways related to DNA repair, E2F targets, and G2M checkpoints; in contrast, transcriptional signatures of the nM group were enriched in interferon responses. Moreover, we observed an impaired induction of interferon responses accompanied by imbalanced cell-intrinsic immune sensing and an excessive inflammatory response in patients with severe disease (nS and vS). In sum, our study provides detailed insights into the systemic immune response to SARS-CoV-2 infection and reveals profound alterations in seven major immune cells in COVID-19 patients.

Update on Innate Immunity in Acute Kidney Injury—Lessons Taken from COVID-19

The serious clinical course of SARS-CoV-2 infection is usually accompanied by acute kidney injury (AKI), worsening prognosis and increasing mortality. AKI in COVID-19 is above all a consequence of systemic dysregulations leading to inflammation, thrombosis, vascular endothelial damage and necrosis. All these processes rely on the interactions between innate immunity elements, including circulating blood cells, resident renal cells, their cytokine products, complement systems, coagulation cascades and contact systems. Numerous simultaneous pathways of innate immunity should secure an effective host defense. Since they all form a network of cross-linked auto-amplification loops, uncontrolled activation is possible. When the actions of selected pathways amplify, cascade activation evades control and the propagation of inflammation and necrosis worsens, accompanied by complement overactivity and immunothrombosis. The systemic activation of innate immunity reaches the kidney, where the damage affecting single tubular cells spreads through tissue collateral damage and triggers AKI. This review is an attempt to synthetize the connections between innate immunity components engaged in COVID-19-related AKI and to summarize the knowledge on the pathophysiological background of processes responsible for renal damage.

A ubiquitous bone marrow reservoir of preexisting SARS-CoV-2-reactive memory CD4+ T lymphocytes in unexposed individuals

Circulating, blood-borne SARS-CoV-2-reactive memory T cells in persons so far unexposed to SARS-CoV-2 or the vaccines have been described in 20-100% of the adult population. They are credited with determining the efficacy of the immune response in COVID-19. Here, we demonstrate the presence of preexisting memory CD4⁺ T cells reacting to peptides of the spike, membrane, or nucleocapsid proteins of SARS-CoV-2 in the bone marrow of all 17 persons investigated that had previously not been exposed to SARS-CoV-2 or one of the vaccines targeting it, with only 15 of these persons also having such cells detectable circulating in the blood. The preexisting SARS-CoV-2-reactive memory CD4⁺ T cells of the bone marrow are abundant and polyfunctional, with the phenotype of central memory T cells. They are tissue-resident, at least in those persons who do not have such cells in the blood, and about 30% of them express CD69. Bone marrow resident SARS-CoV-2-reactive memory CD4⁺ memory T cells are also abundant in vaccinated persons analyzed 10-168 days after 1°-4° vaccination. Apart from securing the bone marrow, preexisting cross-reactive memory CD4⁺ T cells may play an important role in shaping the systemic immune response to SARS-CoV-2 and the vaccines, and contribute essentially to the rapid establishment of long-lasting immunity provided by memory plasma cells, already upon primary infection.

Metabolic dyshomeostasis induced by SARS-CoV-2 structural proteins reveals immunological insights into viral olfactory interactions

One of the most common symptoms in COVID-19 is a sudden loss of smell. SARS-CoV-2 has been detected in the olfactory bulb (OB) from animal models and sporadically in COVID-19 patients. To decipher the specific role over the SARS-CoV-2 proteome at olfactory level, we characterized the in-depth molecular imbalance induced by the expression of GFP-tagged SARS-CoV-2 structural proteins (M, N, E, S) on mouse OB cells. Transcriptomic and proteomic trajectories uncovered a widespread metabolic remodeling commonly converging in extracellular matrix organization, lipid metabolism and signaling by receptor tyrosine kinases. The molecular singularities and specific interactome expression modules were also characterized for each viral structural factor. The intracellular molecular imbalance induced by each SARS-CoV-2 structural protein was accompanied by differential activation dynamics in survival and immunological routes in parallel with a differentiated secretion profile of chemokines in OB cells. Machine learning through a proteotranscriptomic data integration uncovered TGF-beta signaling as a confluent activation node by the SARS-CoV-2 structural proteome. Taken together, these data provide important avenues for understanding the multifunctional immunomodulatory properties of SARS-CoV-2 M, N, S and E proteins beyond their intrinsic role in virion formation, deciphering mechanistic clues to the olfactory inflammation observed in COVID-19 patients.

Gene Network Analysis of the Transcriptome Impact of SARS-CoV-2 Interacting MicroRNAs in COVID-19 Disease

According to the World Health Organization (WHO), as of June 2022, over 536 million confirmed COVID-19 disease cases and over 6.3 million deaths had been globally reported. COVID-19 is a multiorgan disease involving multiple intricated pathological mechanisms translated into clinical, biochemical, and molecular changes, including microRNAs. MicroRNAs are essential post-transcriptional regulators of gene expression, being involved in the modulation of most biological processes. In this study, we characterized the biological impact of SARS-CoV-2 interacting microRNAs differentially expressed in COVID-19 disease by analyzing their impact on five distinct tissue transcriptomes. To this end, we identified the microRNAs’ predicted targets within the list of differentially expressed genes (DEGs) in tissues affected by high loads of SARS-CoV-2 virus. Next, we submitted the tissue-specific lists of the predicted microRNA-targeted DEGs to gene network functional enrichment analysis. Our data show that the upregulated microRNAs control processes such as mitochondrial respiration and cytokine and cell surface receptor signaling pathways in the heart, lymph node, and kidneys. In contrast, downregulated microRNAs are primarily involved in processes related to the mitotic cell cycle in the heart, lung, and kidneys. Our study provides the first exploratory, systematic look into the biological impact of the microRNAs associated with COVID-19, providing a new perspective for understanding its multiorgan physiopathology.

Signaling mechanisms of SARS-CoV-2 Nucleocapsid protein in viral infection, cell death and inflammation

COVID-19 which is caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2) has posed a worldwide pandemic and a major global public health threat. SARS-CoV-2 Nucleocapsid (N) protein plays a critical role in multiple steps of the viral life cycle and participates in viral replication, transcription, and assembly. The primary roles of N protein are to assemble with genomic RNA into the viral RNA-protein (vRNP) complex and to localize to the replication transcription complexes (RTCs) to enhance viral replication and transcription. N protein can also undergo liquid-liquid phase separation (LLPS) with viral genome RNA and inhibit stress granules to facilitate viral replication and assembly. Besides the function in viral life cycle, N protein can bind GSDMD to antagonize pyroptosis but promotes cell death via the Smad3-dependent G1 cell cycle arrest mechanism. In innate immune system, N protein inhibits IFN-β production and RNAi pathway for virus survival. However, it can induce expression of proinflammatory cytokines by activating NF-κB signaling and NLRP3 inflammasome, resulting in cytokine storms. In this review article, we are focusing on the signaling mechanisms of SARS-CoV-2 N protein in viral replication, cell death and inflammation.

Therapy Targets SARS-CoV-2 Infection-Induced Cell Death

Coronavirus Disease 2019 (COVID-19) caused by SARS-CoV-2 has become a global health issue. The clinical presentation of COVID-19 is highly variable, ranging from asymptomatic and mild disease to severe. However, the mechanisms for the high mortality induced by SARS-CoV-2 infection are still not well understood. Recent studies have indicated that the cytokine storm might play an essential role in the disease progression in patients with COVID-19, which is characterized by the uncontrolled release of cytokines and chemokines leading to acute respiratory distress syndrome (ARDS), multi-organ failure, and even death. Cell death, especially, inflammatory cell death, might be the initiation of a cytokine storm caused by SARS-CoV-2 infection. This review summarizes the forms of cell death caused by SARS-CoV-2 in vivo or in vitro and elaborates on the dedication of apoptosis, necroptosis, NETosis, pyroptosis of syncytia, and even SARS-CoV-2 E proteins forming channel induced cell death, providing insights into targets on the cell death pathway for the treatment of COVID-19.