Characterization of the induction kinetics and antiviral functions of IRF1, ISG15 and ISG20 in cells infected with gammacoronavirus avian infectious bronchitis virus.

Coronavirus infection induces a variety of cellular antiviral responses either dependent on or independent of type I interferons (IFNs). Our previous studies using Affymetrix microarray and transcriptomic analysis revealed the differential induction of three IFN-stimulated genes (ISGs), IRF1, ISG15 and ISG20, by gammacoronavirus infectious bronchitis virus (IBV) infection of IFN-deficient Vero cells and IFN-competent, p53-defcient H1299 cells, respectively. In this report, the induction kinetics and anti-IBV functions of these ISGs as well as mechanisms underlying their differential induction are characterized. The results confirmed that these three ISGs were indeed differentially induced in H1299 and Vero cells infected with IBV, significantly more upregulation of IRF1, ISG15 and ISG20 was elicited in IBV-infected Vero cells than that in H1299 cells. Induction of these ISGs was also detected in cells infected with human coronavirus-OC43 (HCoV-OC43) and porcine epidemic diarrhea virus (PEDV), respectively. Manipulation of their expression by overexpression, knockdown and/or knockout demonstrated that IRF1 played an active role in suppressing IBV replication, mainly through the activation of the IFN pathway. However, a minor, if any, role in inhibiting IBV replication was played by ISG15 and ISG20. Furthermore, p53, but not IRF1, was implicated in regulating the IBV infection-induced upregulation of ISG15 and ISG20. This study provides new information on the mechanisms underlying the induction of these ISGs and their contributions to the host cell antiviral response during IBV infection.

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.

Use of a Cytosponge biomarker panel to prioritise endoscopic Barrett's oesophagus surveillance: a cross-sectional study followed by a real-world prospective pilot.

BACKGROUND: Endoscopic surveillance is recommended for patients with Barrett's oesophagus because, although the progression risk is low, endoscopic intervention is highly effective for high-grade dysplasia and cancer. However, repeated endoscopy has associated harms and access has been limited during the COVID-19 pandemic. We aimed to evaluate the role of a non-endoscopic device (Cytosponge) coupled with laboratory biomarkers and clinical factors to prioritise endoscopy for Barrett's oesophagus. METHODS: We first conducted a retrospective, multicentre, cross-sectional study in patients older than 18 years who were having endoscopic surveillance for Barrett's oesophagus (with intestinal metaplasia confirmed by TFF3 and a minimum Barrett's segment length of 1 cm [circumferential or tongues by the Prague C and M criteria]). All patients had received the Cytosponge and confirmatory endoscopy during the BEST2 (ISRCTN12730505) and BEST3 (ISRCTN68382401) clinical trials, from July 7, 2011, to April 1, 2019 (UK Clinical Research Network Study Portfolio 9461). Participants were divided into training (n=557) and validation (n=334) cohorts to identify optimal risk groups. The biomarkers evaluated were overexpression of p53, cellular atypia, and 17 clinical demographic variables. Endoscopic biopsy diagnosis of high-grade dysplasia or cancer was the primary endpoint. Clinical feasibility of a decision tree for Cytosponge triage was evaluated in a real-world prospective cohort from Aug 27, 2020 (DELTA; ISRCTN91655550; n=223), in response to COVID-19 and the need to provide an alternative to endoscopic surveillance. FINDINGS: The prevalence of high-grade dysplasia or cancer determined by the current gold standard of endoscopic biopsy was 17% (92 of 557 patients) in the training cohort and 10% (35 of 344) in the validation cohort. From the new biomarker analysis, three risk groups were identified: high risk, defined as atypia or p53 overexpression or both on Cytosponge; moderate risk, defined by the presence of a clinical risk factor (age, sex, and segment length); and low risk, defined as Cytosponge-negative and no clinical risk factors. The risk of high-grade dysplasia or intramucosal cancer in the high-risk group was 52% (68 of 132 patients) in the training cohort and 41% (31 of 75) in the validation cohort, compared with 2% (five of 210) and 1% (two of 185) in the low-risk group, respectively. In the real-world setting, Cytosponge results prospectively identified 39 (17%) of 223 patients as high risk (atypia or p53 overexpression, or both) requiring endoscopy, among whom the positive predictive value was 31% (12 of 39 patients) for high-grade dysplasia or intramucosal cancer and 44% (17 of 39) for any grade of dysplasia. INTERPRETATION: Cytosponge atypia, p53 overexpression, and clinical risk factors (age, sex, and segment length) could be used to prioritise patients for endoscopy. Further investigation could validate their use in clinical practice and lead to a substantial reduction in endoscopy procedures compared with current surveillance pathways. FUNDING: Medical Research Council, Cancer Research UK, Innovate UK.

Up-regulated 60S ribosomal protein L18 in PEDV N protein-induced S-phase arrested host cells promotes viral replication.

Coronavirus subverts the host cell cycle to create a favorable cellular environment that enhances viral replication in host cells. Previous studies have revealed that nucleocapsid (N) protein of the coronavirus porcine epidemic diarrhea virus (PEDV) interacts with p53 to induce cell cycle arrest in S-phase and promotes viral replication. However, the mechanism by which viral replication is increased in the PEDV N protein-induced S-phase arrested cells remains unknown. In the current study, the protein expression profiles of PEDV N protein-induced S-phase arrested Vero E6 cells and thymidine-induced S-phase arrested Vero E6 cells were characterized by tandem mass tag-labeled quantitative proteomic technology. The effect of differentially expressed proteins (DEPs) on PEDV replication was investigated. The results indicated that a total of 5709 proteins, including 20,560 peptides, were identified, of which 58 and 26 DEPs were identified in the PEDV N group and thymidine group, respectively (P < 0.05; ratio ≥ 1.2 or ≤ 0.8). The unique DEPs identified in the PEDV N group were mainly involved in DNA replication, transcription, and protein synthesis, of which 60S ribosomal protein L18 (RPL18) exhibited significantly up-regulated expression in the PEDV N protein-induced S-phase arrested Vero E6/IPEC-J2 cells and PEDV-infected IPEC-J2 cells (P < 0.05). Further studies revealed that the RPL18 protein could significantly enhance PEDV replication (P < 0.05). Our findings reveal a mechanism regarding increased viral replication when the PEDV N protein-induced host cells are in S-phase arrest. These data also provide evidence that PEDV maintains its own replication by utilizing protein synthesis-associated ribosomal proteins.

P53 in endothelial function and unfolded protein response regulation.

Vascular barrier dysfunction due to endothelial hyperpermeability has been associated with the pathophysiology of sepsis and severe lung injury, which may inflict acute respiratory distress syndrome (ARDS). Our group is focused on the mechanisms operating towards the regulation of endothelial permeability, to contribute in the development of efficient and targeted countermeasures against ARDS. Unfortunately, the number of ARDS-related deaths in the intensive care units has dramatically increased during the COVID-19 era. The findings described herein inform the corresponding scientific and medical community on the relation of P53 and stress responses in barrier function.

Signaling Pathway Reporter Screen with SARS-CoV-2 Proteins Identifies nsp5 as a Repressor of p53 Activity.

The dysregulation of host signaling pathways plays a critical role in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and viral pathogenesis. While a number of viral proteins that can block type I IFN signaling have been identified, a comprehensive analysis of SARS-CoV-2 proteins in the regulation of other signaling pathways that can be critical for viral infection and its pathophysiology is still lacking. Here, we screened the effect of 21 SARS-CoV-2 proteins on 10 different host signaling pathways, namely, Wnt, p53, TGFß, c-Myc, Hypoxia, Hippo, AP-1, Notch, Oct4/Sox2, and NF-κB, using a luciferase reporter assay. As a result, we identified several SARS-CoV-2 proteins that could act as activators or inhibitors for distinct signaling pathways in the context of overexpression in HEK293T cells. We also provided evidence for p53 being an intrinsic host restriction factor of SARS-CoV-2. We found that the overexpression of p53 is capable of reducing virus production, while the main viral protease nsp5 can repress the transcriptional activity of p53, which depends on the protease function of nsp5. Taken together, our results provide a foundation for future studies, which can explore how the dysregulation of specific signaling pathways by SARS-CoV-2 proteins can control viral infection and pathogenesis.

The Role of E3 Ligase Pirh2 in Disease.

The p53-dependent ubiquitin ligase Pirh2 regulates a number of proteins involved in different cancer-associated processes. Targeting the p53 family proteins, Chk2, p27Kip1, Twist1 and others, Pirh2 participates in such cellular processes as proliferation, cell cycle regulation, apoptosis and cellular migration. Thus, it is not surprising that Pirh2 takes part in the initiation and progression of different diseases and pathologies including but not limited to cancer. In this review, we aimed to summarize the available data on Pirh2 regulation, its protein targets and its role in various diseases and pathological processes, thus making the Pirh2 protein a promising therapeutic target.

TP53 Gene Therapy as a Potential Treatment for Patients with COVID-19.

SGT-53 is a novel investigational agent that comprises an immunoliposome carrying a plasmid vector driving expression of the human TP53 gene that encodes wild-type human p53. SGT-53 is currently in phase II human trials for advanced pancreatic cancer. Although p53 is best known as a tumor suppressor, its participation in both innate and adaptive immune responses is well documented. It is now clear that p53 is an important component of the host response to various viral infections. To facilitate their viral life cycles, viruses have developed a diverse repertoire of strategies for counteracting the antiviral activities of host immune system by manipulating p53-dependent pathways in host cells. Coronaviruses reduce endogenous p53 levels in the cells they infect by enhancing the degradation of p53 in proteasomes. Thus, interference with p53 function is an important component in viral pathogenesis. Transfection of cells by SGT-53 has been shown to transiently produce exogenous p53 that is active as a pleiotropic transcription factor. We herein summarize the rationale for repurposing SGT-53 as a therapy for infection by SARS-CoV-2, the pathogen responsible for the COVID-19 pandemic. Because p53 regulation was found to play a crucial role in different infection stages of a wide variety of viruses, it is rational to believe that restoring p53 function based on SGT-53 treatment may lead to beneficial therapeutic outcomes for infectious disease at large including heretofore unknown viral pathogens that may emerge in the future.

A Practical Strategy for Exploring the Pharmacological Mechanism of Luteolin Against COVID-19/Asthma Comorbidity: Findings of System Pharmacology and Bioinformatics Analysis.

Asthma patients may increase their susceptibility to SARS-CoV-2 infection and the poor prognosis of coronavirus disease 2019 (COVID-19). However, anti-COVID-19/asthma comorbidity approaches are restricted on condition. Existing evidence indicates that luteolin has antiviral, anti-inflammatory, and immune regulation capabilities. We aimed to evaluate the possibility of luteolin evolving into an ideal drug and explore the underlying molecular mechanisms of luteolin against COVID-19/asthma comorbidity. We used system pharmacology and bioinformatics analysis to assess the physicochemical properties and biological activities of luteolin and further analyze the binding activities, targets, biological functions, and mechanisms of luteolin against COVID-19/asthma comorbidity. We found that luteolin may exert ideal physicochemical properties and bioactivity, and molecular docking analysis confirmed that luteolin performed effective binding activities in COVID-19/asthma comorbidity. Furthermore, a protein-protein interaction network of 538 common targets between drug and disease was constructed and 264 hub targets were obtained. Then, the top 6 hub targets of luteolin against COVID-19/asthma comorbidity were identified, namely, TP53, AKT1, ALB, IL-6, TNF, and VEGFA. Furthermore, the enrichment analysis suggested that luteolin may exert effects on virus defense, regulation of inflammation, cell growth and cell replication, and immune responses, reducing oxidative stress and regulating blood circulation through the Toll-like receptor; MAPK, TNF, AGE/RAGE, EGFR, ErbB, HIF-1, and PI3K-AKT signaling pathways; PD-L1 expression; and PD-1 checkpoint pathway in cancer. The possible "dangerous liaison" between COVID-19 and asthma is still a potential threat to world health. This research is the first to explore whether luteolin could evolve into a drug candidate for COVID-19/asthma comorbidity. This study indicated that luteolin with superior drug likeness and bioactivity has great potential to be used for treating COVID-19/asthma comorbidity, but the predicted results still need to be rigorously verified by experiments.

MYC Expression Is Associated With p53 Expression and TP53 Aberration and Predicts Poor Overall Survival in Acute Lymphoblastic Leukemia/Lymphoma.

OBJECTIVES: We evaluated MYC and p53 expression, TP53 aberration, their relationship, and their impact on overall survival (OS) in acute lymphoblastic leukemia (ALL)/lymphoblastic lymphoma (LBL). METHODS: We identified 173 patients with ALL and LBL, including 12 cases of mixed-phenotype acute leukemia, 8 cases of therapy-related B-cell ALL (B-ALL), 119 cases of B-ALL, and 34 cases of T-cell ALL/LBL diagnosed from 2003 to 2019. We retrospectively assessed p53 and MYC expression by immunohistochemistry of bone marrow and correlated MYC expression with p53 expression and TP53 aberration. RESULTS: Expression of p53 and MYC was present in 11.5% and 27.7% of ALL/LBL cases (n = 20 and n = 48), respectively. MYC expression was significantly correlated with p53 expression and TP53 aberration (P = .002 and P = .03), and p53 expression and MYC expression had an adverse impact on OS in patients with ALL/LBL (P < .05). MYC and p53 dual expression as well as combined MYC expression and TP53 aberration had a negative impact on OS in patients with ALL/LBL. CONCLUSIONS: MYC expression is correlated with p53 overexpression, TP53 aberration, and poor OS in patients with ALL/LBL.

Nanoparticle encapsulation of non-genotoxic p53 activator Inauhzin-C for improved therapeutic efficacy.

The tumor suppressor protein p53 remains in a wild type but inactive form in ~50% of all human cancers. Thus, activating it becomes an attractive approach for targeted cancer therapies. In this regard, our lab has previously discovered a small molecule, Inauhzin (INZ), as a potent p53 activator with no genotoxicity. Method: To improve its efficacy and bioavailability, here we employed nanoparticle encapsulation, making INZ-C, an analog of INZ, to nanoparticle-encapsulated INZ-C (n-INZ-C). Results: This approach significantly improved p53 activation and inhibition of lung and colorectal cancer cell growth by n-INZ-C in vitro and in vivo while it displayed a minimal effect on normal human Wi38 and mouse MEF cells. The improved activity was further corroborated with the enhanced cellular uptake observed in cancer cells and minimal cellular uptake observed in normal cells. In vivo pharmacokinetic evaluation of these nanoparticles showed that the nanoparticle encapsulation prolongates the half-life of INZ-C from 2.5 h to 5 h in mice. Conclusions: These results demonstrate that we have established a nanoparticle system that could enhance the bioavailability and efficacy of INZ-C as a potential anti-cancer therapeutic.

Coronavirus Porcine Epidemic Diarrhea Virus Nucleocapsid Protein Interacts with p53 To Induce Cell Cycle Arrest in S-Phase and Promotes Viral Replication.

Subversion of the host cell cycle to facilitate viral replication is a common feature of coronavirus infections. Coronavirus nucleocapsid (N) protein can modulate the host cell cycle, but the mechanistic details remain largely unknown. Here, we investigated the effects of manipulation of porcine epidemic diarrhea virus (PEDV) N protein on the cell cycle and the influence on viral replication. Results indicated that PEDV N induced Vero E6 cell cycle arrest at S-phase, which promoted viral replication (P < 0.05). S-phase arrest was dependent on the N protein nuclear localization signal S71NWHFYYLGTGPHADLRYRT90 and the interaction between N protein and p53. In the nucleus, the binding of N protein to p53 maintained consistently high-level expression of p53, which activated the p53-DREAM pathway. The key domain of the N protein interacting with p53 was revealed to be S171RGNSQNRGNNQGRGASQNRGGNN194 (NS171-N194), in which G183RG185 are core residues. NS171-N194 and G183RG185 were essential for N-induced S-phase arrest. Moreover, small molecular drugs targeting the NS171-N194 domain of the PEDV N protein were screened through molecular docking. Hyperoside could antagonize N protein-induced S-phase arrest by interfering with interaction between N protein and p53 and inhibit viral replication (P < 0.05). The above-described experiments were also validated in porcine intestinal cells, and data were in line with results in Vero E6 cells. Therefore, these results reveal the PEDV N protein interacts with p53 to activate the p53-DREAM pathway, and subsequently induces S-phase arrest to create a favorable environment for virus replication. These findings provide new insight into the PEDV-host interaction and the design of novel antiviral strategies against PEDV. IMPORTANCE Many viruses subvert the host cell cycle to create a cellular environment that promotes viral growth. PEDV, an emerging and reemerging coronavirus, has led to substantial economic loss in the global swine industry. Our study is the first to demonstrate that PEDV N-induced cell cycle arrest during the S-phase promotes viral replication. We identified a novel mechanism of PEDV N-induced S-phase arrest, where the binding of PEDV N protein to p53 maintains consistently high levels of p53 expression in the nucleus to mediate S-phase arrest by activating the p53-DREAM pathway. Furthermore, a small molecular compound, hyperoside, targeted the PEDV N protein, interfering with the interaction between the N protein and p53 and, importantly, inhibited PEDV replication by antagonizing cell cycle arrest. This study reveals a new mechanism of PEDV-host interaction and also provides a novel antiviral strategy for PEDV. These data provide a foundation for further research into coronavirus-host interactions.

Screening out anti-inflammatory or anti-viral targets in Xuanfei Baidu Tang through a new technique of reverse finding target.

Traditional Chinese herbal compound prescription in Xuanfei Baidu Tang (XBT) has obvious effects in the treatment of COVID-19. However, its effective compounds and targets for the treatment of COVID-19 remain unclear. Computer-Aided Drug Design is used to virtually screen out the anti-inflammatory or anti-viral compounds in XBT, and predict the potential targets by Discovery Studio 2020. Then, we searched for COVID-19 targets using Genecards databases and Protein Data Bank (PDB) databases and compared them to identify targets that were common to both. Finally, the target we screened out is: TP53 (Tumor Protein P53). This article also shows that XBT in the treatment of COVID-19 works in a multi-link and overall synergistic manner. Our results will help to design the new drugs for COVID-19.

Can Glycosylation Mask the Detection of MHC Expressing p53 Peptides by T Cell Receptors?

Proteins of the major histocompatibility complex (MHC) class I, or human leukocyte antigen (HLA) in humans interact with endogenous peptides and present them to T cell receptors (TCR), which in turn tune the immune system to recognize and discriminate between self and foreign (non-self) peptides. Of especial importance are peptides derived from tumor-associated antigens. T cells recognizing these peptides are found in cancer patients, but not in cancer-free individuals. What stimulates this recognition, which is vital for the success of checkpoint based therapy? A peptide derived from the protein p53 (residues 161-169 or p161) was reported to show this behavior. T cells recognizing this unmodified peptide could be further stimulated in vitro to create effective cancer killing CTLs (cytotoxic T lymphocytes). We hypothesize that the underlying difference may arise from post-translational glycosylation of p161 in normal individuals, likely masking it against recognition by TCR. Defects in glycosylation in cancer cells may allow the presentation of the native peptide. We investigate the structural consequences of such peptide glycosylation by investigating the associated structural dynamics.

Induction of the NEK family of kinases in the lungs of mice subjected to cecal ligation and puncture model of sepsis.

Endothelial barrier dysfunction (EBD) is the hallmark of Acute Respiratory Distress Syndrome (ARDS), a potentially lethal respiratory disorder associated with the COVID-19 - related deaths. Herein, we employed a cecal ligation and puncture (CLP) murine model of sepsis, to evaluate the effects of sepsis-induced EBD in the expression of the never in mitosis A (NIMA)-related kinases (NEKs). Members of that family of kinases regulate the activity and expression of the tumor suppressor P53, previously shown to modulate the actin cytoskeleton remodeling. Our results introduce the induction of NEK2, NEK3, NEK4, NEK7, and NEK9 in a CLP model of sepsis. Hence, we suggest that NEKs are involved in inflammatory processes and are holding the potential to serve as novel therapeutic targets for pathologies related to EBD, including ARDS and sepsis. Further studies will delineate the underlying molecular events and their interrelations with P53.

Implementing a method for engineering multivalency to substantially enhance binding of clinical trial anti-SARS-CoV-2 antibodies to wildtype spike and variants of concern proteins.

Infection by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes COVID-19 disease. Therapeutic antibodies are being developed that interact with the viral spike proteins to limit viral infection of epithelium. We have applied a method to dramatically improve the performance of anti-SARS-CoV-2 antibodies by enhancing avidity through multimerization using simple engineering to yield tetrameric antibodies. We have re-engineered six anti-SARS-CoV-2 antibodies using the human p53 tetramerization domain, including three clinical trials antibodies casirivimab, imdevimab and etesevimab. The method yields tetrameric antibodies, termed quads, that retain efficient binding to the SARS-CoV-2 spike protein, show up to two orders of magnitude enhancement in neutralization of pseudovirus infection and retain potent interaction with virus variant of concern spike proteins. The tetramerization method is simple, general and its application is a powerful methodological development for SARS-CoV-2 antibodies that are currently in pre-clinical and clinical investigation.

Activation of p21 limits acute lung injury and induces early senescence after acid aspiration and mechanical ventilation.

The p53/p21 pathway is activated in response to cell stress. However, its role in acute lung injury has not been elucidated. Acute lung injury is associated with disruption of the alveolo-capillary barrier leading to acute respiratory distress syndrome (ARDS). Mechanical ventilation may be necessary to support gas exchange in patients with ARDS, however, high positive airway pressures can cause regional overdistension of alveolar units and aggravate lung injury. Here, we report that acute lung injury and alveolar overstretching activate the p53/p21 pathway to maintain homeostasis and avoid massive cell apoptosis. A systematic pooling of transcriptomic data from animal models of lung injury demonstrates the enrichment of specific p53- and p21-dependent gene signatures and a validated senescence profile. In a clinically relevant, murine model of acid aspiration and mechanical ventilation, we observed changes in the nuclear envelope and the underlying chromatin, DNA damage and activation of the Tp53/p21 pathway. Absence of Cdkn1a decreased the senescent response, but worsened lung injury due to increased cell apoptosis. Conversely, treatment with lopinavir and/or ritonavir led to Cdkn1a overexpression and ameliorated cell apoptosis and lung injury. The activation of these mechanisms was associated with early markers of senescence, including expression of senescence-related genes and increases in senescence-associated heterochromatin foci in alveolar cells. Autopsy samples from lungs of patients with ARDS revealed increased senescence-associated heterochromatin foci. Collectively, these results suggest that acute lung injury activates p53/p21 as an antiapoptotic mechanism to ameliorate damage, but with the side effect of induction of senescence.

A tissue- and gender-specific regulation of the SARS-CoV-2 receptor ACE2 by p53 in pigs.

The current COVID-19 pandemic is caused by infections with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A sex-bias has been observed, with increased susceptibility and mortality in male compared to female patients. The gene for the SARS-CoV-2 receptor ACE2 is located on the X chromosome. We previously generated TP53 mutant pigs that exhibit a sex-specific patho-phenotype due to altered regulation of numerous X chromosome genes. In this study, we explored the effect of p53 deficiency on ACE2 expression in pigs. First, we identified the p53 binding site in the ACE2 promoter and could show its regulatory effect on ACE2 expression by luciferase assay in porcine primary kidney fibroblast cells. Later, quantitative PCR and western blot showed tissue- and gender-specific expression changes of ACE2 and its truncated isoform in p53-deficient pigs. We believe these findings will broaden the knowledge on ACE2 regulation and COVID-19 susceptibility.

The unbalanced p53/SIRT1 axis may impact lymphocyte homeostasis in COVID-19 patients.

BACKGROUND/OBJECTIVES: A dysregulated inflammatory profile plays an important role in coronavirus disease-2019 (COVID-19) pathogenesis. Moreover, the depletion of lymphocytes is typically associated with an unfavourable disease course. We studied the role and impact of p53 and deacetylase Sirtuin 1 (SIRT1) on lymph-monocyte homeostasis and their possible effect on T and B cell signalling. METHODS: Gene expression analysis and flow cytometry were performed on peripheral blood mononuclear cells (PBMC) of 35 COVID-19 patients and 10 healthy donors (HD). Inflammatory cytokines, the frequency of Annexin+ cells among CD3+ T cells and CD19+ B cell subsets were quantified. RESULTS: PBMC from COVID-19 patients had a higher p53 expression, and higher concentrations of plasma proinflammatory cytokines (IL1ß, TNF-α, IL8, and IL6) than HD. Deacetylase Sirtuin 1 (SIRT1) expression was significantly decreased in COVID-19 patients and was negatively correlated with p53 (p = 0.003 and r = -0.48). A lower expression of IL-7R and B Cell linker (BLNK), key genes for lymphocyte homeostasis and function, was observed in COVID-19 than in HD. The reduction of IgK and IgL chains was seen in lymphopenic COVID-19 patients. A significant increase in both apoptotic B and T cells were observed. Inflammatory cytokines correlated positively with p53 (IL-1ß: r = 0.5 and p = 0.05; IL-8: r = 0.5 and p = 0.05) and negatively with SIRT1 (IL1-ß: r = -0.5 and p = 0.04; TNF-α: r = -0.4 and p = 0.04). CONCLUSIONS: Collectively, our data indicate that the inflammatory environment, the dysregulated p53/SIRT1 axis and low expression of IL7R and BLNK may impact cell survival, B cell signalling and antibody production in COVID-19 patients. Further studies are required to define the functional impact of low BLNK/IL7R expression during severe acute respiratory syndrome coronavirus-2 infection.