Role of the cAMP-PKA-NF-κB pathway in Mucin1 over-expression in A549 cells during Respiratory syncytial virus infection.

Respiratory syncytial virus (RSV) is the most common pathogen associated with acute lower respiratory tract infections in infants and young children worldwide. RSV commonly presents as bronchiolitis in young children; however, it can sometimes progress to pneumonia, respiratory failure, apnoea and even death. Although mucin1 (MUC1), a type of transmembrane glycoprotein present on airway epithelial surfaces, plays a crucial anti-inflammatory role in airway infections; however, its roles in RSV-associated acute lower respiratory tract infections have rarely been explored. In this study, we first revealed very high MUC1 protein levels in the exacerbation phase in sputum samples from children with RSV bronchiolitis. Because MUC1 is the downstream target of tumour necrosis factor-alpha (TNF-α) in RSV-infected A549 cells, we observed the inhibition of NF-κB activity, main downstream signalling of TNF-α and remarkably reduced levels of MUC1 in RSV-infected and TNF-α treated A549 cells. Furthermore, the cyclic adenosine monophosphate (cAMP) analogue (dbcAMP) downregulated the protein levels of p-IκBα and MUC1 in TNF-α-treated A549 cells. By contrast, a protein kinase A inhibitor (KT5720) up-regulated the levels of those proteins. dbcAMP and KT5720 had the same effects on MUC1 protein levels in RSV-infected A549 cells. In conclusion, we found that the cAMP-PKA-NF-κB pathway may play a role in the regulation of MUC-1 over-expression during RSV infection.

Successful clearance of persistent SARS-CoV-2 asymptomatic infection following a single dose of Ad5-nCoV vaccine.

Persistent asymptomatic (PA) SARS-CoV-2 infections have been identified. The immune responses in these patients are unclear, and the development of effective treatments for these patients is needed. Here, we report a cohort of 23 PA cases carrying viral RNA for up to 191 days. PA cases displayed low levels of inflammatory and interferon response, weak antibody response, diminished circulating follicular helper T cells (cTfh), and inadequate specific CD4+ and CD8+ T-cell responses during infection, which is distinct from symptomatic infections and resembling impaired immune activation. Administration of a single dose of Ad5-nCoV vaccine to 10 of these PA cases elicited rapid and robust antibody responses as well as coordinated B-cell and cTfh responses, resulting in successful viral clearance. Vaccine-induced antibodies were able to neutralize various variants of concern and persisted for over 6 months, indicating long-term protection. Therefore, our study provides an insight into the immune status of PA infections and highlights vaccination as a potential treatment for prolonged SARS-CoV-2 infections.

Mouse models susceptible to HCoV-229E and HCoV-NL63 and cross protection from challenge with SARS-CoV-2.

Human coronavirus 229E (HCoV-229E) and NL63 (HCoV-NL63) are endemic causes of upper respiratory infections such as the "common cold" but may occasionally cause severe lower respiratory tract disease in the elderly and immunocompromised patients. There are no approved antiviral drugs or vaccines for these common cold coronaviruses (CCCoV). The recent emergence of COVID-19 and the possible cross-reactive antibody and T cell responses between these CCCoV and SARS-CoV-2 emphasize the need to develop experimental animal models for CCCoV. Mice are an ideal experimental animal model for such studies, but are resistant to HCoV-229E and HCoV-NL63 infections. Here, we generated 229E and NL63 mouse models by exogenous delivery of their receptors, human hAPN and hACE2 using replication-deficient adenoviruses (Ad5-hAPN and Ad5-hACE2), respectively. Ad5-hAPN- and Ad5-hACE2-sensitized IFNAR-/- and STAT1-/- mice developed pneumonia characterized by inflammatory cell infiltration with virus clearance occurring 7 d post infection. Ad5-hAPN- and Ad5-hACE2-sensitized mice generated virus-specific T cells and neutralizing antibodies after 229E or NL63 infection, respectively. Remdesivir and a vaccine candidate targeting spike protein of 229E and NL63 accelerated viral clearance of virus in these mice. 229E- and NL63-infected mice were partially protected from SARS-CoV-2 infection, likely mediated by cross-reactive T cell responses. Ad5-hAPN- and Ad5-hACE2-transduced mice are useful for studying pathogenesis and immune responses induced by HCoV-229E and HCoV-NL63 infections and for validation of broadly protective vaccines, antibodies, and therapeutics against human respiratory coronaviruses including SARS-CoV-2.

The N-Terminal Region of Middle East Respiratory Syndrome Coronavirus Accessory Protein 8b Is Essential for Enhanced Virulence of an Attenuated Murine Coronavirus.

Middle East respiratory syndrome coronavirus (MERS-CoV) is a beta coronavirus that emerged in 2012, causing severe pneumonia and renal failure. MERS-CoV encodes five accessory proteins. Some of them have been shown to interfere with host antiviral immune response. However, the roles of protein 8b in innate immunity and viral virulence was rarely studied. Here, we introduced individual MERS-CoV accessory protein genes into the genome of an attenuated murine coronavirus (Mouse hepatitis virus, MHV), respectively, and found accessory protein 8b could enhance viral replication in vivo and in vitro and increase the lethality of infected mice. RNA-seq analysis revealed that protein 8b could significantly inhibit type I interferon production (IFN-I) and innate immune response in mice infected with MHV expressing protein 8b. We also found that MERS-CoV protein 8b could initiate from multiple internal methionine sites and at least three protein variants were identified. Residues 1-23 of protein 8b was demonstrated to be responsible for increased virulence in vivo. In addition, the inhibitory effect on IFN-I of protein 8b might not contribute to its virulence enhancement as aa1-23 deletion did not affect IFN-I production in vitro and in vivo. Next, we also found that protein 8b was localized to the endoplasmic reticulum (ER)/Golgi membrane in infected cells, which was disrupted by C-terminal region aa 88-112 deletion. This study will provide new insight into the pathogenesis of MERS-CoV infection. IMPORTANCE Multiple coronaviruses (CoV) cause severe respiratory infections and become global public health threats such as SARS-CoV, MERS-CoV, and SARS-CoV-2. Each coronavirus contains different numbers of accessory proteins which show high variability among different CoVs. Accessory proteins are demonstrated to play essential roles in pathogenesis of CoVs. MERS-CoV contains 5 accessory proteins (protein 3, 4a, 4b, 5, 8b), and deletion of all four accessory proteins (protein 3, 4a, 4b, 5), significantly affects MERS-CoV replication and pathogenesis. However, whether ORF8b also regulates MERS-CoV infection is unknown. Here, we constructed mouse hepatitis virus (MHV) recombinant virus expressing MERS-CoV protein 8b and demonstrated protein 8b could significantly enhance the virulence of MHV, which is mediated by N-terminal domain of protein 8b. This study will shed light on the understanding of pathogenesis of MERS-CoV infection.

Case report: A case of SLC26A4 mutations causing pendred syndrome and non-cystic fibrosis bronchiectasis.

The SLC26A4 gene encodes the transmembrane protein pendrin, which is involved in the ion transport of chloride (Cl-), iodide (I-) or bicarbonate (HCO3-). Mutations in the SLC26A4 gene alter the structure and (or) function of pendrin, which are closely related to Pendred syndrome. What's more, researchers have demonstrated in vitro that mutations of SLC26A4 cause acidification of airway surface fluid (ASL), reduce airway defense, and increase the thickness of ASL. In the context of infection, it may lead to chronic inflammation, destruction of airway wall architecture and bronchiectasis. However, there is no case report of bronchiectasis caused by SLC26A4 gene mutations. Here, we describe the first case of Pendred syndrome and non-cystic fibrosis bronchiectasis in a child possibly caused by SLC26A4 mutations. We remind clinicians to pay attention to the possibility of bronchiectasis in patients with SLC26A4 gene mutations.

Potent prophylactic and therapeutic efficacy of recombinant human ACE2-Fc against SARS-CoV-2 infection in vivo.

The current COVID-19 pandemic, caused by SARS-CoV-2, poses a serious public health threat. Effective therapeutic and prophylactic treatments are urgently needed. Angiotensin-converting enzyme 2 (ACE2) is a functional receptor for SARS-CoV-2, which binds to the receptor binding domain (RBD) of SARS-CoV-2 spike protein. Here, we developed recombinant human ACE2-Fc fusion protein (hACE2-Fc) and a hACE2-Fc mutant with reduced catalytic activity. hACE2-Fc and the hACE2-Fc mutant both efficiently blocked entry of SARS-CoV-2, SARS-CoV, and HCoV-NL63 into hACE2-expressing cells and inhibited SARS-CoV-2 S protein-mediated cell-cell fusion. hACE2-Fc also neutralized various SARS-CoV-2 strains with enhanced infectivity including D614G and V367F mutations, as well as the emerging SARS-CoV-2 variants, B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617.1 (Kappa), and B.1.617.2 (Delta), demonstrating its potent and broad-spectrum antiviral effects. In addition, hACE2-Fc proteins protected HBE from SARS-CoV-2 infection. Unlike RBD-targeting neutralizing antibodies, hACE2-Fc treatment did not induce the development of escape mutants. Furthermore, both prophylactic and therapeutic hACE2-Fc treatments effectively protected mice from SARS-CoV-2 infection, as determined by reduced viral replication, weight loss, histological changes, and inflammation in the lungs. The protection provided by hACE2 showed obvious dose-dependent efficacy in vivo. Pharmacokinetic data indicated that hACE2-Fc has a relative long half-life in vivo compared to soluble ACE2, which makes it an excellent candidate for prophylaxis and therapy for COVID-19 as well as for SARS-CoV and HCoV-NL63 infections.

Peripheral immune profile of children with Talaromyces marneffei infections: a retrospective analysis of 21 cases.

BACKGROUND: Talaromyces marneffei (T. marneffei) is an opportunistic pathogen that infects immunodeficient children. The aim of the study is to determine the clinical features and peripheral immune state of Talaromyces marneffei (T. marneffei) infections in children for early detection and diagnosis. METHODS: We retrospectively reviewed 21 pediatric patients who were diagnosed with T. marneffei infections and were followed up in the Guangzhou Women and Children's Medical Center from January 2010 to January 2020. For each patient, we collected and analyzed clinical characteristics, peripheral immunological results, genetic tests, complications and prognosis. RESULTS: Common clinical features of the patients included fever (20/21, 95.24%), cough (17/21, 80.95%) and hepatomegaly (17/21, 80.95%). Severe complications included septic shock (12/21, 57.14%), hemophagocytic lymphohistiocytosis (HLH) (11/21, 52.38%), acute respiratory distress syndrome (ARDS) (10/21, 47.62%), multiple organ dysfunction syndrome (MODS) (9/21, 42.86%), and disseminated intravascular coagulation (DIC) (7/21, 33.33%). Eleven children (11/21, 52.38%) eventually died of T. marneffei infections. All patients were HIV negative. Seven cases revealed reduced antibody levels, especially IgG. Higher levels of IgE were detected in 9 cases with an obvious increase in two patients. Ten patients showed decreased complement C3 levels, some of whom had low C4 levels. Three patients displayed decreased absolute T lymphocyte counts, including the CD 4+ and CD 8+ subsets. A reduction in NK cells was present in most patients. No patient had positive nitro blue tetrazolium (NBT) test results. Nine patients were screened for common genetic mutations. Of the cases, one case had no disease-specific gene mutation. Four children had confirmed hyperimmunoglobulin M syndrome (HIGM) with CD40LG variation, one case had severe combined immunodeficiency (SCID), and one case had hyper-IgE syndrome (HIES). One patient was identified as having a heterozygous mutation in STAT3 gene; however, he showed no typical clinical manifestations of HIES at his age. One patient had a mutated COPA gene with uncertain pathogenic potential. Another patient was diagnosed with HIES that depended on her clinical features and the National Institutes of Health (NIH) scoring system. CONCLUSIONS: T. marneffei infections in HIV-negative children induced severe systemic complications and poor prognosis. Children with T. marneffei infections commonly exhibited abnormal immunoglobulin levels in peripheral blood, particularly decreased IgG or increased IgE levels, further suggesting possible underlying PIDs in these patients.

MiR-320a-3p/ELF3 axis regulates cell metastasis and invasion in non-small cell lung cancer via PI3K/Akt pathway.

MicroRNAs (miRNAs) play important roles in tumorigenesis and tumor progression. In this study, we investigated the role of miR-320a-3p in non-small cell lung cancer (NSCLC). Expressions of miR-320a-3p were firstly determined in 80 NSCLC patients' cancer tissues and adjacent normal lung tissues by qRT-PCR. Then MTT assay, cell migration and invasion assays were performed in vitro. Potential binding sites on target gene of miR-320a-3p were predicted and luciferase reporter assay was used to identify the potential binding sites. Tumorigenesis assay were performed in nude mice by injecting A549 cells which stably express miR-320a-3p. Results indicated that high expression of miR-320a-3p suppresses cell proliferation, migration and invasion through the inactivation of PI3K/Akt signaling pathway in NSCLC cells. Smaller tumor size and lighter weight were also found in nude mice which had miR-320a-3p higher expressed. Furthermore, data from luciferase reporter assay proved the direct binding of miR-320a-3p on the 3'UTR region of ELF3 mRNA, this could further decrease ELF3 expression transcriptionally. We provided evidence that miR-320a-3p might work as a tumor suppressor in NSCLC both in vivo and in vitro.

Scrub typhus associated with hemophagocytic lymphohistiocytosis: A report of six pediatric patients.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune disorder that may be inherited or secondary to infection, malignancy or rheumatological disease. The aim of the present study was to highlight the clinical features of scrub typhus-associated HLH in children. A retrospective study was performed on 6 pediatric patients with scrub typhus-associated HLH. For each patient, medical records were reviewed and analyzed, and demographic, clinical and laboratory data and outcomes were collected. The duration of fever prior to admission ranged between 4 and 12 days. All patients exhibited persistent or intermittent fever, eschar, hepatosplenomegaly and lymphadenopathy at the time of diagnosis. Five patients experienced acute respiratory distress syndrome and disseminated intravascular coagulation (DIC) during hospitalization. Thrombocytopenia was detected in all patients with cytopenia involving two or three cell types, simultaneously. Coagulopathy with prolonged prothrombin time and/or activated partial thromboplastin time were noted in all patients. Markedly elevated serum ferritin levels (>1,500 µg/ml) were identified in all patients. Elevated lactate dehydrogenase (>1,000 U/l) was detected in 4 (66.7%) patients and elevated alanine aminotransferase was exhibited by 5 (83/3%) patients. Lung infiltrates and consolidation were the most common imaging findings. Only 1 patient succumbed, with DIC and multi-organ failure. Of the survivors, 1 patient was lost to follow-up, and the remaining patients are in remission with excellent general health, to date. In conclusion, HLH should be considered in severe pediatric cases of scrub typhus. Upon the early recognition of this syndrome, prompt and supportive treatment in the pediatric intensive care unit are vital.

Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis: a retrospective study of 78 pediatric cases in mainland of China.

BACKGROUND: The clinical characteristics of Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) are largely unreported in the pediatric patients in mainland of China. The main aim of this study was to recognize the clinical features of EBV-HLH in children and to explore its prognosis and risk factors. METHODS: A retrospective study was performed on 78 pediatric patients with EBV-HLH who were admitted to Beijing Children's Hospital between 2003 and 2008. All patients' medical records were reviewed and analyzed. For each patient, demographic, clinical, laboratory and outcome information was collected. Statistical analysis was conducted via multivariate and univariate analysis. RESULTS: The age of onset peaked between 1 - 2 years and boys were more likely developed EBV-HLH. EBV-HLH occurred mainly in the serological pattern with EBV nuclear antigen (EBNA) positive (70.5%). The overall fatality of the disease was 56.7%. Twelve of the 39 fatalities (30.8%) died rapidly within 2 months after diagnosis. Multivariate analysis revealed that not receiving chemotherapy (P = 0.002), > or = 4 weeks of illness prior to diagnosis (P = 0.004), and albumin levels < 20 g/L (P = 0.045) significantly predicted an increased fatality risk. CONCLUSIONS: EBV-HLH is a severe disease with a high fatality rate that occurs mainly in the serological pattern with EBNA positive. Early initiation of chemotherapy and timely diagnosis significantly improves survival rate. Practical strategies should focus on reducing the likelihood of early death.

Characterization of variants in the promoter of BZLF1 gene of EBV in nonmalignant EBV-associated diseases in Chinese children.

BACKGROUND: Diseases associated with Epstein-Barr virus (EBV) infections, such as infectious mononucleosis (IM), EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH) and chronic active EBV infection (CAEBV) are not rare in Chinese children. The association of type 1 or type 2 EBV and variants of the EBV BZLF1 promoter zone (Zp) with these diseases is unclear. RESULTS: The objective of this study was to investigate the relationship between EBV genotypes (Zp variants and EBV type 1 and 2) and the clinical phenotypes of EBV-associated diseases in Chinese children. The Zp region was directly sequenced in 206 EBV-positive DNA samples from the blood of patients with IM, EBV-HLH, CAEBV, and healthy controls. Type 1 or type 2 EBV was examined by PCR for EBNA2 and EBNA3C subtypes. Four polymorphic Zp variants were identified: Zp-P, Zp-V3, Zp-P4 and Zp-V1, a new variant. The Zp-V3 variant was significantly associated with CAEBV (P 0.05). CONCLUSIONS: Type 1 EBV and BZLF1 Zp-P of EBV were the predominant genotypes in nonmalignant EBV associated diseases in Chinese children and Zp-V3 variant may correlates with the developing of severe EBV infection diseases, such as CAEBV and EBV-HLH.

[Clinical analysis and follow-up study of Epstein-Barr virus associated-hemophagocytic lymphohistiocytosis in childhood].

OBJECTIVE: To identify the clinical characteristics of and to explore the prognostic factors influencing mortality in children with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH). METHOD: A retrospective study was conducted on 62 pediatric patients with EBV-HLH who were admitted to our hospital between 2003 and 2008. All their medical records were reviewed and analyzed. For each patient, demographic, clinical and laboratory data, genetic findings and outcome information were collected. The patients were divided into two groups: deceased or survived based on the follow-up results. Comparative analysis of the data was done by using independent-samples t test and Logistic multiple and univariate regression. RESULT: (1) Among the 62 EBV-HLH patients, 36 were male and 26 were female. The age of onset ranged from 2 months to 14 years and most of the patients were between 1 and 3 years of age. EBV-HLH occurred mainly in the setting of reactivation (61.3%). (2) All patients exhibited persistent or intermittent fever and cytopenia >/= 2 cell lines. Most of the patients presented with hepatomegaly (83.9%), splenomegaly (72.6%) and lymphadenopathy (69.4%). The main laboratory features showed an elevation of serum ferritin and aminotransferase levels. A reduction in serum albumin was observed and exhibited coagulopathy with hypofibrinogenemia and hypertriglyceridemia in most of the patients. Forty-eight of patients had hemophagocytosis in bone marrow at diagnosis of EBV-HLH. The serum EBV DNA level in 14 of 31 patients with EBV-HLH was in the range of 5.12 x 10(2) - 7.69 x 10(7) copies/ml with a mean value of 10(3.9) copies/ml. (3) Three heterozygous mutations in coding region were found, which resulted in amino acid change (C102F, S108N and T450M) in 3 patients. One patient had compound heterozygous mutations (S108N and T450M) in the PRF1 gene as the background defect and documented familial HLH type 2 (FHL2). (4) During the observational period, 35 of 57 patients (61.4%) died 3 months to 3 years after the onset, while 21 of whom died despite aggressive polychemotherapy, 15 of whom died within 2 months after hospitalization. The deceased patients were more likely to have lower albumin level and more prolonged activated partial thromboplastin time than the survived patients (P < 0.05 for all comparisons). Multivariate Logistic regression analysis revealed that duration of illness >/= 1 month, non-chemotherapy, albumin level < / = 25 microg/L and internal organs hemorrhage were related with the prognosis significantly (P < 0.05 for all comparisons). CONCLUSION: This study revealed that EBV-HLH infection in pediatric patients had severe clinical courses and prognosis was poor and the majority of cases underwent EBV reactivation. The early diagnosis, prompt and proper chemotherapy can improve the survival rate. The duration of illness >/= 1 month, non-chemotherapy, decreases in albumin and internal organs hemorrhage were the risk factors related to mortality in children with EBV-HLH.

Clinical analysis and follow-up study of chronic active Epstein-Barr virus infection in 53 pediatric cases.

BACKGROUND: Chronic active Epstein-Barr virus infection (CAEBV) has been previously reported to be sometimes associated with an aggressive clinical course. The characteristics of CAEBV in Mainland Chinese pediatric patients are largely unreported. The main aims of this survey were to recognize the clinical features of CAEBV in children and to explore its diagnostic criteria and risk factors. METHODS: A retrospective study was performed on 53 pediatric patients (36 boys and 17 girls) with CAEBV who were admitted to Beijing Children's Hospital between 2003 and 2007. All their medical records were reviewed and analyzed. For each patient, demographic, clinical, laboratory data and outcome were collected. Independent-samples t test was used for statistical analysis. RESULTS: The age at onset of CAEBV was from 2 months to 14.6 years (mean (5.3+/-3.3) years). At the time of onset, 43.4% patients had an infectious mononucleosis-like symptom. Most patients exhibited intermittent fever (92.5%, 49/53), hepatomegaly (81.1%, 43/53) and splenomegaly (77.4%, 41/53). Life-threatening complications including hemophagocytic syndrome (24.5%, 13/53), interstitial pneumonia (24.5%, 13/53), hepatic failure (15.1%, 8/53) and malignant lymphoma (11.3%, 6/53) were also observed. The serum EBV DNA level in 23 patients with CAEBV was in the range of 5.05 x 10(2)-4.60 x 10(6) copies/ml with a mean value of 10(3.7) copies/ml. Many patients with CAEBV generally had continuous symptoms during the observational period. Eleven out of 42 patients (26.2%) died 7 months to 3 years after onset. Deceased patients were more likely to have had lower platelet counts and albumin levels than the living patients (P<0.05 for all comparisons). CONCLUSIONS: The study reveals that CAEBV in Chinese pediatric patients has a severe clinical course and prognosis is poor. Thrombocytopenia and decreases in albumin might potentially be risk factors for a poor prognosis. EBV loads should be measured and tissue should be stained on hybridization probes for EBV-encoded small RNA (EBER) if a patient presents with the known symptoms of CAEBV.

Mutations in the perforin gene in children with hemophagocytic lymphohistiocytosis.

BACKGROUND: Recent studies have reported germline mutations in the perforin gene (PRF1) in some types of hemophagocytic lymphohistiocytosis (HLH). However, the prevalence of PRF1 mutations in HLH in Chinese pediatric patients has not been extensively studied. The aim of this study was to investigate the prevalence of mutations and sequence variations in the PRF1 gene in Chinese pediatric patients with HLH. METHODS: Polymerase chain reaction (PCR) was performed with five pairs of primers for the coding exons and the flanking intron sequences of PRF1. Sequencing of PCR products was subsequently applied in 30 pediatric patients with HLH and in 50 controls. RESULTS: Three heterozygous mutations in a coding region were found, which resulted in amino acid changes (C102F, S108N and T450M) in three patients. These mutations were not detected in control subjects. One patient had compound heterozygous mutations (S108N and T450M) in PRF1 as the background defect, and documented familial HLH type 2 (FHL2). One synonymous sequence variant (Q540Q) was observed in one patient but not in the controls. Two SNPs (A274A, H300H) in the coding region were detected in HLH patients and controls, but without differences in the heterozygosity rate between the two groups (P > 0.05 for all comparisons). CONCLUSIONS: We have identified three patients with three heterozygous missense mutations in PRF1; two of those three mutations (C102F and S108N) have so far been found only from Chinese patients. These findings are useful in evaluating the prevalence of PRF1 mutations in Chinese pediatric patients with HLH, and to correlate their genotype with phenotype. Some patients without familial history probably have primary HLH, which should be suspected even beyond the usual age range.