Caveats of chimpanzee ChAdOx1 adenovirus-vectored vaccines to boost anti-SARS-CoV-2 protective immunity in mice

Several COVID-19 vaccines use adenovirus vectors to deliver the SARS-CoV-2 spike (S) protein. Immunization with these vaccines promotes immunity against the S protein, but against also the adenovirus itself. This could interfere with the entry of the vaccine into the cell, reducing its efficacy. Herein, we evaluate the efficiency of an adenovirus-vectored vaccine (chimpanzee ChAdOx1 adenovirus, AZD1222) in boosting the specific immunity compared to that induced by a recombinant receptor-binding domain (RBD)-based vaccine without viral vector. Mice immunized with the AZD1222 human vaccine were given a booster 6 months later, with either the homologous vaccine or a recombinant vaccine based on RBD of the delta variant, which was prevalent at the start of this study. A significant increase in anti-RBD antibody levels was observed in rRBD-boosted mice (31-61%) compared to those receiving two doses of AZD1222 (0%). Significantly higher rates of PepMix™- or RBD-elicited proliferation were also observed in IFNγ-producing CD4 and CD8 cells from mice boosted with one or two doses of RBD, respectively. The lower efficiency of the ChAdOx1-S vaccine in boosting specific immunity could be the result of a pre-existing anti-vector immunity, induced by increased levels of anti-adenovirus antibodies found both in mice and humans. Taken together, these results point to the importance of avoiding the recurrent use of the same adenovirus vector in individuals with immunity and memory against them. It also illustrates the disadvantages of ChAdOx1 adenovirus-vectored vaccine with respect to recombinant protein vaccines, which can be used without restriction in vaccine-booster programs. KEY POINTS: • ChAdOx1 adenovirus vaccine (AZD1222) may not be effective in boosting anti-SARS-CoV-2 immunity • A recombinant RBD protein vaccine is effective in boosting anti-SARS-CoV-2 immunity in mice • Antibodies elicited by the rRBD-delta vaccine persisted for up to 3 months in mice.

The functional TNFAIP3 rs2230926T/G (Phe127Cys) variant confers risk to systemic lupus erythematosus in a Latin American population

TNFAIP3 is a classical systemic lupus erythematosus (SLE)-associated risk locus identified by genome-wide association studies (GWASs) and replicated by candidate gene association studies primarily in Caucasians and Asians. However, in Latin American populations, its role on SLE susceptibility is not known. We conducted a case-control study to evaluate whether the TNFAIP3 rs2230926T/G (Phe127Cys) variant is associated with risk of developing SLE in a cohort of Mexican patients. The TNFAIP3 rs2230926T/G variant was analyzed in 561 patients with SLE and 499 control subjects, using TaqMan probes. We found that the G allele was associated with susceptibility to SLE under the allelic (OR 2.09, p = 0.005) and genotypic (OR 2.14, p = 0.004) models. In conclusion, our results show that TNFAIP3 rs2230926T/G is a risk factor for the development of SLE in the Mexican population.

Combination of Recombinant Proteins S1/N and RBD/N as Potential Vaccine Candidates

Despite all successful efforts to develop a COVID-19 vaccine, the need to evaluate alternative antigens to produce next-generation vaccines is imperative to target emerging variants. Thus, the second generation of COVID-19 vaccines employ more than one antigen from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to induce an effective and lasting immune response. Here, we analyzed the combination of two SARS-CoV-2 viral antigens that could elicit a more durable immune response in both T- and B-cells. The nucleocapsid (N) protein, Spike protein S1 domain, and receptor binding domain (RBD) of the SARS-CoV-2 spike surface glycoproteins were expressed and purified in a mammalian expression system, taking into consideration the posttranscriptional modifications and structural characteristics. The immunogenicity of these combined proteins was evaluated in a murine model. Immunization combining S1 or RBD with the N protein induced higher levels of IgG antibodies, increased the percentage of neutralization, and elevated the production of cytokines TNF-α, IFN-γ, and IL-2 compared to the administration of a single antigen. Furthermore, sera from immunized mice recognized alpha and beta variants of SARS-CoV-2, which supports ongoing clinical results on partial protection in vaccinated populations, despite mutations. This study identifies potential antigens for second-generation COVID-19 vaccines.

Convalescent Plasma to Treat COVID-19: A Two-Center, Randomized, Double-Blind Clinical Trial

Background: The use of convalescent plasma (CP) has been considered for its immunological mechanisms that could benefit patients in moderate and severe stages of COVID-19. This study evaluated the safety and efficacy of the use of donor CP for COVID-19. Material and methods: A double-blind, randomized controlled clinical trial was conducted from May to October 2020. Thirty-nine participants with moderate (II) and severe (III) stages of COVID-19 confirmed by RT-PCR were included. The study randomization rate was set at 3:1. CPs were chosen for application with a neutralizing antibody titer of ≥1:32. Results: We observed a significantly lower 21-day post-transfusion mortality HR: 0.17 (95.0% CI [0.07−0.45, p < 0.001]) in the group receiving CP compared with the control group; protective units (PU) in the group receiving convalescent plasma after seven days were significantly higher (512 (32−16,384) vs. 96 (32−256), p = 0.01); the PAO2/FIO2 index showed a significant improvement in the group receiving CP (251.01 (109.4) vs. 109.2 (62.4), p < 0.001, in the control group). Conclusion: CP is safe and effective, as it decreased mortality in the CP group compared with the control group.

A(H3N2) antigenic variation of influenza is associated with low vaccine efficacy in the early 2018 influenza season in Mexico City

OBJECTIVES

We evaluated the VE and the mutations of the viruses present in the Mexican population at the beginning of 2018.

METHODS

We diagnosed influenza in outpatients with a high-performance Rapid Influenza Diagnostic Test (RIDT) qRT-PCR. Descriptive statistics were used to describe the study population, while the chi-square test was used to determine clinical variables. VE was analyzed through a negative test design. We sequenced the hemagglutinin (HA) gene, performed a phylogenetic analysis, and analyzed the nonsynonymous substitutions both in and outside antigenic sites.

RESULTS

Of the 240 patients analyzed, 42.5% received the trivalent vaccine, and 37.5% were positive for influenza. The VE for the general population for any influenza virus type or subtype was 37.0%, while the VE for the predominant influenza A(H3N2) subtype was the lowest (19.7%). The phylogenetic analysis of HA showed the co-circulation of clades and subclades 3C.2a1, 3C.2a1b, 3C.2a2, 3C.2a2re, 3C.2a3, and 3C.3a with identities approximately 97-98% similar to the vaccine composition.

CONCLUSION

Low VE was related to the co-circulation of multiple clades and subclades of influenza A(H3N2), with sufficient genetic and phenotypic distance to allow for the infection of vaccinated individuals.

A potent virucidal activity of functionalized TiO2 nanoparticles adsorbed with flavonoids against SARS-CoV-2

Abstract

The coronavirus SARS-CoV-2 has caused a pandemic with > 550 millions of cases and > 6 millions of deaths worldwide. Medical management of COVID-19 relies on supportive care as no specific targeted therapies are available yet. Given its devastating effects on the economy and mental health, it is imperative to develop novel antivirals. An ideal candidate will be an agent that blocks the early events of viral attachment and cell entry, thereby preventing viral infection and spread. This work reports functionalized titanium dioxide (TiO₂)-based nanoparticles adsorbed with flavonoids that block SARS-CoV-2 entry and fusion. Using molecular docking analysis, two flavonoids were chosen for their specific binding to critical regions of the SARS-CoV-2 spike glycoprotein that interacts with the host cell angiotensin-converting enzyme-2 (ACE-2) receptor. These flavonoids were adsorbed onto TiO₂ functionalized nanoparticles (FTNP). This new nanoparticulate compound was assayed in vitro against two different coronaviruses; HCoV 229E and SARS-CoV-2, in both cases a clear antiviral effect was observed. Furthermore, using a reporter-based cell culture model, a potent antiviral activity is demonstrated. The adsorption of flavonoids to functionalized TiO₂ nanoparticles induces a ~ threefold increase of that activity. These studies also indicate that FTNP interferes with the SARS-CoV-2 spike, impairing the cell fusion mechanism.

Key points/Highlights

• Unique TiO₂nanoparticles displaying flavonoid showed potent anti-SARS-CoV-2 activity.

• The nanoparticles precisely targeting SARS-CoV-2 were quantitatively verified by cell infectivity in vitro.

• Flavonoids on nanoparticles impair the interactions between the spike glycoprotein and ACE-2 receptor.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00253-022-12112-9.

An RBD-Based Diagnostic Method Useful for the Surveillance of Protective Immunity against SARS-CoV-2 in the Population

After more than two years, the COVID-19 pandemic is still ongoing and evolving all over the world; human herd immunity against SARS-CoV-2 increases either by infection or by unprecedented mass vaccination. A substantial change in population immunity is expected to contribute to the control of transmission. It is essential to monitor the extension and duration of the population’s immunity to support the decisions of health authorities in each region and country, directed to chart the progressive return to normality. For this purpose, the availability of simple and cheap methods to monitor the levels of relevant antibodies in the population is a widespread necessity. Here, we describe the development of an RBD-based ELISA for the detection of specific antibodies in large numbers of samples. The recombinant expression of an RBD-poly-His fragment was carried out using either bacterial or eukaryotic cells in in vitro culture. After affinity chromatography purification, the performance of both recombinant products was compared by ELISA in similar trials. Our results showed that eukaryotic RBD increased the sensitivity of the assay. Interestingly, our results also support a correlation of the eukaryotic RBD-based ELISA with other assays aimed to test for neutralizing antibodies, which suggests that it provides an indication of protective immunity against SARS-CoV-2.

TNFSF4 is a risk factor for rheumatoid arthritis but not for primary Sjögren's syndrome in the Mexican population

PURPOSE

Rheumatoid arthritis (RA) and primary Sjögren's syndrome (pSS) are autoimmune diseases (ADs) characterized by joint damage and involvement of the salivary glands, respectively. ADs share some susceptibility loci, such as TNFSF4, which is a classical susceptibility gene associated with systemic lupus erythematosus, but its role in RA and pSS is not yet clear. Thus, the aim of this study was to determine whether three TNFSFS4 polymorphisms are associated with RA and pSS.

METHODS

Our case-control study included 500 controls, 459 patients with RA, and 210 patients with pSS from Mexico. TNFSF4 single nucleotide polymorphisms (SNPs) rs1234315C/T, rs2205960G/T, and rs704840T/G were genotyped using TaqMan probes and discrimination allelic assay.

RESULTS

The three TNFSF4 SNPs were associated with susceptibility to RA (rs1234315C/T: odds ratio [OR] 1.4, p = 0.01; rs2205960G/T: OR 1.23, p = 0.03; rs704840T/G: OR 1.24, p = 0.02). An association between TNFSF4 rs1234315C/T and pSS was also observed (OR 1.28, p = 0.04), however, after Bonferroni correction, this association was lost.

CONCLUSION

Our data suggest that TNFSF4 could be a risk factor in RA but not pSS in a Mexican population.

The Entry Blocker Peptide Produced in Chlamydomonas reinhardtii Inhibits Influenza Viral Replication in vitro

This year, a respiratory virus caused an emergency pandemic alert in health services around the world, showing the need for biotechnological approaches to fight these diseases. The influenza virus is one of the main viral agents that generate pandemic outbreaks. Currently, the majority of co-circulating influenza A virus (IAV) strains are adamantine- and oseltamivir-resistant strains, and the challenge is to find new antivirals for more efficient treatments. The antiviral entry blocker (EB) peptide is a promising candidate for blocking the virus entry into cells. The aim of this research was to express the EB peptide in the microalgae Chlamydomonas reinhardtii and test its antiviral activity against IAV in vitro. The EB peptide nucleotide sequence was introduced into the nuclear genome of microalgae using Agrobacterium tumefaciens transformation. The EB peptide amount produced in transformed microalgae was 4.99 ± 0.067% of the total soluble protein. In hemagglutination inhibition assays using influenza A/H1N1 pdm and influenza A H1N1/Virginia/ATCC/2009 strains, we reported that the EB peptide extract from the microalgae showed 100-fold higher efficiency than the EB synthetic peptide. In addition, both the EB peptide extract and synthetic peptide inhibited viral replication in MDCK cells (IC50 = 20.7 nM and IC50 = 754.4 nM, respectively); however, the EB peptide extract showed a 32-fold higher antiviral effectiveness than the synthetic peptide against influenza A/H1N1 pdm. Extracts from untransformed and transformed microalgae and synthetic peptide did not show cytotoxic effect on MDCK cell monolayers. Thus, C. reinhardtii may be a fast, safe, and effective expression platform for production of peptides with significant antiviral activity and can be used as a prophylactic treatment to reduce viral propagation.

Clinical and Immunological Factors That Distinguish COVID-19 From Pandemic Influenza A(H1N1)

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), is a global health threat with the potential to cause severe disease manifestations in the lungs. Although COVID-19 has been extensively characterized clinically, the factors distinguishing SARS-CoV-2 from other respiratory viruses are unknown. Here, we compared the clinical, histopathological, and immunological characteristics of patients with COVID-19 and pandemic influenza A(H1N1). We observed a higher frequency of respiratory symptoms, increased tissue injury markers, and a histological pattern of alveolar pneumonia in pandemic influenza A(H1N1) patients. Conversely, dry cough, gastrointestinal symptoms and interstitial lung pathology were observed in COVID-19 cases. Pandemic influenza A(H1N1) was characterized by higher levels of IL-1RA, TNF-α, CCL3, G-CSF, APRIL, sTNF-R1, sTNF-R2, sCD30, and sCD163. Meanwhile, COVID-19 displayed an immune profile distinguished by increased Th1 (IL-12, IFN-γ) and Th2 (IL-4, IL-5, IL-10, IL-13) cytokine levels, along with IL-1β, IL-6, CCL11, VEGF, TWEAK, TSLP, MMP-1, and MMP-3. Our data suggest that SARS-CoV-2 induces a dysbalanced polyfunctional inflammatory response that is different from the immune response against pandemic influenza A(H1N1). Furthermore, we demonstrated the diagnostic potential of some clinical and immune factors to differentiate both diseases. These findings might be relevant for the ongoing and future influenza seasons in the Northern Hemisphere, which are historically unique due to their convergence with the COVID-19 pandemic.

BLK and BANK1 variants and interactions are associated with susceptibility for primary Sjögren's syndrome and with some clinical features

BLK and BANK1 in primary Sjögren's syndrome (pSS) have scarcely been evaluated and the results are inconclusive. The aim of our study was to determine whether single nucleotide variants (SNVs) located within BLK or BANK1 are associated with susceptibility, clinical and serological features, and smoking in pSS. BLK rs13277113A/G, BANK1 rs10516487G/A and rs3733197G/A were genotyped in 203 cases and 424 controls using a TaqMan® SNP genotyping assay. The BLK rs13277113A allele showed association with pSS under the allelic (OR 1.35, p = 0.02), and recessive (OR 1.83, p = 0.003) model, while, BANK1 rs3733197G/A showed association under the dominant model (OR 2.90, p = 0.043). Interactions between BANK1 and BLK genotypes also showed association (OR 2.36, p < 0.0001). In addition, BLK rs13277113A/G was associated with protection against arthritis and BANK1 rs10516487G/A with both arthritis and keratoconjunctivitis sicca, meanwhile, BANK1 rs3733197G/A was associated with smoking in patients with pSS. This is the first study to describe an association between BLK and susceptibility to pSS in a Latin-American population. Our data also shows a first evidence of association between interactions of BLK and BANK1 in pSS, and association of BLK and BANK1with arthritis, keratoconjunctivitis sicca and smoking in patients with pSS.

CXCL17 Is a Specific Diagnostic Biomarker for Severe Pandemic Influenza A(H1N1) That Predicts Poor Clinical Outcome

The C-X-C motif chemokine ligand 17 (CXCL17) is chemotactic for myeloid cells, exhibits bactericidal activity, and exerts anti-viral functions. This chemokine is constitutively expressed in the respiratory tract, suggesting a role in lung defenses. However, little is known about the participation of CXCL17 against relevant respiratory pathogens in humans. Here, we evaluated the serum levels and lung tissue expression pattern of CXCL17 in a cohort of patients with severe pandemic influenza A(H1N1) from Mexico City. Peripheral blood samples obtained on admission and seven days after hospitalization were processed for determinations of serum CXCL17 levels by enzyme-linked immunosorbent assay (ELISA). The expression of CXCL17 was assessed by immunohistochemistry (IHQ) in lung autopsy specimens from patients that succumbed to the disease. Serum CXCL17 levels were also analyzed in two additional comparative cohorts of coronavirus disease 2019 (COVID-19) and pulmonary tuberculosis (TB) patients. Additionally, the expression of CXCL17 was tested in lung autopsy specimens from COVID-19 patients. A total of 122 patients were enrolled in the study, from which 68 had pandemic influenza A(H1N1), 24 had COVID-19, and 30 with PTB. CXCL17 was detected in post-mortem lung specimens from patients that died of pandemic influenza A(H1N1) and COVID-19. Interestingly, serum levels of CXCL17 were increased only in patients with pandemic influenza A(H1N1), but not COVID-19 and PTB. CXCL17 not only differentiated pandemic influenza A(H1N1) from other respiratory infections but showed prognostic value for influenza-associated mortality and renal failure in machine-learning algorithms and regression analyses. Using cell culture assays, we also identified that human alveolar A549 cells and peripheral blood monocyte-derived macrophages increase their CXCL17 production capacity after influenza A(H1N1) pdm09 virus infection. Our results for the first time demonstrate an induction of CXCL17 specifically during pandemic influenza A(H1N1), but not COVID-19 and PTB in humans. These findings could be of great utility to differentiate influenza and COVID-19 and to predict poor prognosis specially at settings of high incidence of pandemic A(H1N1). Future studies on the role of CXCL17 not only in severe pandemic influenza, but also in seasonal influenza, COVID-19, and PTB are required to validate our results.

Effect of coinfection with influenza virus and bacteria on host damage

Background

Influenza virus infection is often complicated by a bacterial infection, with this coinfection causing severe pneumonia. If not timely treated, the disease can cause death.

Objective

To demonstrate, in animal models, that coinfection with influenza virus and bacteria that affect the respiratory tract causes multisystemic damage.

Method

Six groups of mice were formed: a control group, one infected with the influenza virus, two infected with bacteria: Haemophilus influenzae and Streptococcus pneumoniae, respectively; and two co-infected with influenza virus and Haemophilus influenzae or Streptococcus pneumoniae, respectively.

Results

Of the six groups of mice, only the group co-infected with influenza virus and Streptococcus pneumoniae showed damage to thoracic and abdominal organs. A decrease in serum cytokine levels was found in all study groups, which was more pronounced in the co-infected mice.

Conclusions

The groups of mice infected with Streptococcus pneumoniae or influenza virus alone showed no damage, which indicates that coexistence of these infections caused the damage in the group of co-infected mice.

High performance of rapid influenza diagnostic test and variable effectiveness of influenza vaccines in Mexico

OBJECTIVES

To evaluate the performance of rapid influenza diagnostic tests (RIDT) and influenza vaccines' effectiveness (VE) during an outbreak setting.

METHODS

We compared the performance of a RIDT with RT-PCR for influenza virus detection in influenza-like illness (ILI) patients enrolled during the 2016/17 season in Mexico City. Using the test-negative design, we estimated influenza VE in all participants and stratified by age, virus subtype, and vaccine type (trivalent vs quadrivalent inactivated vaccines). The protective value of some clinical variables was evaluated by regression analyses.

RESULTS

We enrolled 592 patients. RT-PCR detected 93 cases of influenza A(H1N1)pdm09, 55 of AH3N2, 141 of B, and 13 A/B virus infections. RIDT showed 90.7% sensitivity and 95.7% specificity for influenza A virus detection, and 91.5% sensitivity and 95.3% specificity for influenza B virus detection. Overall VE was 33.2% (95% CI: 3.0-54.0; p = 0.02) against any laboratory-confirmed influenza infection. VE estimates against influenza B were higher for the quadrivalent vaccine. Immunization and occupational exposure were protective factors against influenza.

CONCLUSIONS

The RIDT was useful to detect influenza cases during an outbreak setting. Effectiveness of 2016/17 influenza vaccines administered in Mexico was low but significant. Our data should be considered for future local epidemiological policies.

Crosstalk between coagulation and inflammation during Dengue virus infection

Dengue fever is the most prevalent viral disease transmitted by vectors (Aedes aegypti, Aedes albopictus) in worldwide. More than 100 million cases occur annually with a mortality rate of 5% and no safe vaccine is available. The pathogenesis of Dengue, where host and viral factors participate in the establishment of Dengue haemorrhagic fever (DHF) and Dengue shock syndrome (DSS) remains unresolved. Clinical observations have revealed significant abnormalities in coagulation and inflammation systems, with increased levels of tissue factor (TF) and the chemokine IL-8, correlating with the severity of the disease and implicating damage to endothelial vascular cells (EVC). Here we present novel insights concerning the crosstalk between the regulatory signaling pathways of the coagulation-inflammation processes, during Dengue virus (DV) infection of EVC. We found that DV up-regulates Protease Activated receptor type-1 (inflammation) and TF (coagulation) receptors, via the phosphorylation of p38 and ERK1/2 MAPKs, which favor the activation of NF-κB transcription factor. This induces pro-inflammatory (IL-8) or pro-adhesive (VCAM-1) gene expression which may lead to EVC activation. The elucidation of the basic principles that signal these processes has important implications for the design of new therapeutic strategies for DHF/DSS.

Modification of the cytoprotective protein C pathway during Dengue virus infection of human endothelial vascular cells

Dengue fever (DF) is the most prevalent arthropod-borne viral disease of humans. No safe vaccine is available, there is no experimental animal model and no specific treatment (antiviral) for Dengue virus (DV) infection exists. The pathogenic mechanisms of the severe forms of the disease, such as Dengue shock syndrome (DSS) and Dengue haemorrhagic fever (DHF), in which endothelial damage is the pathognomonic sign, are not fully understood. Clinical observations have revealed significant abnormalities in the coagulation and inflammation systems, with increased levels of soluble thrombomodulin (sTM) in the plasma of patients with DHF/DSS (grade III or IV). Blood sTM was proposed as an early predictor of DSS during the febrile stage. However, the role of the DV in endothelial injury during DSS is unclear. Here, we present novel insights into the participation of DV in the downregulation of the thrombomodulin-thrombin-protein C complex formation at the endothelial surface, with a reduction in activated protein C (APC). APC is the most important vasoprotective protein because it downregulates thrombin generation (by the inactivation of procoagulant factors Va and VIIIa) and has anti-inflammatory, antiapoptotic, and barrier protection properties. These biological functions of APC are associated with the endothelial protein C receptor (EPCR) and pro-tease-activated receptor 1 (PAR-1) signalling pathways, which link the coagulation-inflammation responses. We found alterations in the antithrombotic and cytoprotective protein C pathways during DV infection of human endothelial vascular cells, which may explain the vasculopathy observed during DHF/DSS. Clarification of the basic principles that underlie these processes has important implications for the design of new therapeutic strategies for DHF/DSS.

Effects of 2-methoxyestradiol on apoptosis and HIF-1α and HIF-2α expression in lung cancer cells under normoxia and hypoxia

Hypoxic tumor cells are known to be more resistant to conventional chemotherapy and radiation than normoxic cells. However, the effects of 2-methoxyestradiol (2-ME), an anti-angiogenic, antiproliferative and pro-apoptotic drug, on hypoxic lung cancer cells are unknown. The aim of the present study was to compare the effects of 2-ME on cell growth, apoptosis, hypoxia-inducible factor 1α (HIF-1α) and HIF-2α gene and protein expression in A549 cells under normoxic and hypoxic conditions. To establish the optimal 2-ME concentration with which to carry out the apoptosis assay and to examine mRNA and protein expression of HIFs, cell growth analysis was carried out through N-hexa-methylpararosaniline staining assays in A549 cell cultures treated with one of five different 2-ME concentrations at different times under normoxic or hypoxic growth conditions. The 2-ME concentration of 10 mM at 72 h was selected to perform all further experiments. Apoptotic cells were analyzed by flow cytometry. Western blotting was used to determine HIF-1α and HIF-2α protein expression in total cell extracts. Cellular localization of HIF-1α and HIF-2α was assessed by immunocytochemistry. HIF-1α and HIF-2α gene expression was determined by real-time PCR. A significant increase in the percentage of apoptosis was observed when cells were treated with 2-ME under a normoxic but not under hypoxic conditions (p=0.006). HIF-1α and HIF-2α protein expression levels were significantly decreased in cells cultured under hypoxic conditions and treated with 2-ME (p<0.001). Furthermore, 2-ME decreased the HIF-1α and HIF-2α nuclear staining in cells cultured under hypoxia. The HIF-1α and HIF-2α mRNA levels were significantly lower when cells were exposed to 2-ME under normoxia and hypoxia. Our results suggest that 2-ME could have beneficial results when used with conventional chemotherapy in an attempt to lower the invasive and metastatic processes during cancer development due to its effects on the gene expression and protein synthesis of HIFs.

Parasitic polymorphism of Coccidioides spp

BACKGROUND

Coccidioides spp. is the ethiological agent of coccidioidomycosis, an infection that can be fatal. Its diagnosis is complicated, due to that it shares clinical and histopathological characteristics with other pulmonary mycoses. Coccidioides spp. is a dimorphic fungus and, in its saprobic phase, grows as a mycelium, forming a large amount of arthroconidia. In susceptible persons, arthroconidia induce dimorphic changes into spherules/endospores, a typical parasitic form of Coccidioides spp. In addition, the diversity of mycelial parasitic forms has been observed in clinical specimens; they are scarcely known and produce errors in diagnosis.

METHODS

We presented a retrospective study of images from specimens of smears with 15% potassium hydroxide, cytology, and tissue biopsies of a histopathologic collection from patients with coccidioidomycosis seen at a tertiary-care hospital in Mexico City.

RESULTS

The parasitic polymorphism of Coccidioides spp. observed in the clinical specimens was as follows: i) spherules/endospores in different maturation stages; ii) pleomorphic cells (septate hyphae, hyphae composed of ovoid and spherical cells, and arthroconidia), and iii) fungal ball formation (mycelia with septate hyphae and arthroconidia).

CONCLUSIONS

The parasitic polymorphism of Coccidioides spp. includes the following: spherules/endospores, arthroconidia, and different forms of mycelia. This knowledge is important for the accurate diagnosis of coccidioidomycosis. In earlier studies, we proposed the integration of this diversity of forms in the Coccidioides spp. parasitic cycle. The microhabitat surrounding the fungus into the host would favor the parasitic polymorphism of this fungus, and this environment may assist in the evolution toward parasitism of Coccidioides spp.

Modification of the cytoprotective protein C pathway during Dengue virus infection of human endothelial vascular cells

Dengue fever (DF) is the most prevalent arthropod-borne viral disease of humans. No safe vaccine is available, there is no experimental animal model and no specific treatment (antiviral) for Dengue virus (DV) infection exists. The pathogenic mechanisms of the severe forms of the disease, such as Dengue shock syndrome (DSS) and Dengue haemorrhagic fever (DHF), in which endothelial damage is the pathognomonic sign, are not fully understood. Clinical observations have revealed significant abnormalities in the coagulation and inflammation systems, with increased levels of soluble thrombomodulin (sTM) in the plasma of patients with DHF/DSS (grade III or IV). Blood sTM was proposed as an early predictor of DSS during the febrile stage. However, the role of the DV in endothelial injury during DSS is unclear. Here, we present novel insights into the participation of DV in the downregulation of the thrombomodulin-thrombin-protein C complex formation at the endothelial surface, with a reduction in activated protein C (APC). APC is the most important vasoprotective protein because it downregulates thrombin generation (by the inactivation of procoagulant factors Va and VIIIa) and has anti-inflammatory, antiapoptotic, and barrier protection properties. These biological functions of APC are associated with the endothelial protein C receptor (EPCR) and protease-activated receptor 1 (PAR-1) signalling pathways, which link the coagulation-inflammation responses. We found alterations in the antithrombotic and cytoprotective protein C pathways during DV infection of human endothelial vascular cells, which may explain the vasculopathy observed during DHF/DSS. Clarification of the basic principles that underlie these processes has important implications for the design of new therapeutic strategies for DHF/DSS.

Crosstalk between coagulation and inflammation during Dengue virus infection

Dengue fever is the most prevalent viral disease transmitted by vectors (Aedes aegypti, Aedes albopictus) in worldwide. More than 100 million cases occur annually with a mortality rate of 5% and no safe vaccine is available. The pathogenesis of Dengue, where host and viral factors participate in the establishment of Dengue haemorrhagic fever (DHF) and Dengue shock syndrome (DSS) remains unresolved. Clinical observations have revealed significant abnormalities in coagulation and inflammation systems, with increased levels of tissue factor (TF) and the chemokine IL-8, correlating with the severity of the disease and implicating damage to endothelial vascular cells (EVC). Here we present novel insights concerning the crosstalk between the regulatory signaling pathways of the coagulation-inflammation processes, during Dengue virus (DV) infection of EVC. We found that DV up-regulates Protease Activated receptor type-1 (inflammation) and TF (coagulation) receptors, via the phosphorylation of p38 and ERK1/2 MAPKs, which favor the activation of NF-kappaB transcription factor. This induces pro-inflammatory (IL-8) or pro-adhesive (VCAM-1) gene expression which may lead to EVC activation. The elucidation of the basic principles that signal these processes has important implications for the design of new therapeutic strategies for DHF/DSS.