[Corrigendum] NLRP3 inflammasome is responsible for Hantavirus inducing interleukin­1ß in THP­1 cells.

Subsequently to the publication of the above article, the authors have realized that an error was introduced in the preparation of Fig. 2B for publication. In Fig. 2B, the lanes shown for the western blot were misannotated. Additionally, in the legend of Fig. 2C, '24 h post­infection' should have been written as '12 h post­infection'. Furthermore, the description of the data shown in Fig. 2B in the Results section (sentence commencing on p. 1635, the subsection 'HTNV activates caspase­1 and pro­IL­1ß in THP­1 cells', line 10), was incomplete. The sentence here should have read as follows (the added text is highlighted in bold): 'In order to investigate whether caspase­1 was activated during HTNV infection, the culture supernatant of HTNV­infected THP­1 was ultra­ï¬ltered and an increased concentration of secreted caspase­1 was detected post­infection compared with the Mock group; similar results were also observed in the LPS­ and ATP­stimulated groups (Fig. 2B)'. The correct version of Fig. 2, with the lanes of the western blot in Fig. 2B labelled correctly and the appropriate changes having been made to the Figure legend, is shown opposite. The errors associated with this Figure did not have an impact on the overall meaning of the paper, or on the reported conclusions of this study. The authors regret that this Figure was not corrected prior to the publication of this article, and apologize to the readership for any inconvenience caused. [the original article was published in International Journal of Molecular Medicine 35: 1633­1640, 2015; DOI: 10.3892/ijmm.2015.2162].

NLRP3 inflammasome is responsible for Hantavirus inducing interleukin-1ß in THP-1 cells.

Persistent high fever is one typical clinical symptom of hemorrhagic fever with renal syndrome (HFRS) and circulating interleukin-1ß (IL-1ß) is elevated throughout HFRS. The mechanisms responsible for viral induction of IL-1ß secretion are unknown. In the present study, Hantaan virus (HTNV) induced the secretion of IL-1ß in the human monocytic cell line THP-1. Induction of IL-1ß by HTNV relies on the activation of caspase-1. Small hairpin RNA knockdown in HTNV-infected THP-1 cells indicated that nucleotide-binding domain, leucine-rich repeat containing protein 3 (NLRP3) recruits the adaptor apoptosis-associated speck-like protein and caspase-1 to form an NLRP3 inflammasome complex, crucial for the induction of IL-1ß. In HTNV-infected THP-1 cells, reactive oxygen species release, but not extracellular adenosine triphosphate, was crucial for IL-1ß production. In conclusion, Hantavirus induces the formation of the NLRP3 inflammasome in THP-1 cells and this may be responsible for the elevated IL-1ß levels in HFRS patients.

Hantaan virus can infect human keratinocytes and activate an interferon response through the nuclear translocation of IRF-3.

Hantaan virus (HTNV) is a rodent-borne virus that causes hemorrhagic fever with renal syndrome (HFRS) in Asia and can be transmitted to humans through bites or the inhalation of aerosolized urine, droppings, or saliva of infected rodents. Keratinocytes predominate in the epidermis and reportedly serve as a replication site for multiple vector-borne viruses, little is known about the susceptibility of human skin cells to HTNV infection. Therefore, we aimed to evaluate whether human keratinocytes support HTNV replication and elicit an immune response against HTNV infection. We found that a human keratinocyte cell line, HaCaT, supports HTNV replication. In addition, retinoic acid inducible gene-I (RIG-I) and melanoma differentiation associated gene-5 (MDA5) play key roles in the detection of HTNV infection in HaCaT cells and in the up-regulation of interferon (IFN)-ß expression, which subsequently leads to the production of a large amount of antiviral interferon-stimulated genes (ISGs) and other chemokines used for immune cell recruitment. Furthermore, we suggest that interferon regulatory factor (IRF)-3, as opposed to NF-κB/p65 or IRF-7, is translocated to the nucleus to induce IFN-ß. However, the early induction of chemokine CXCL10 was a direct result of HaCaT cells counteracting HTNV infection and was not due to the induction of IFN. Overall, our data demonstrate, for the first time, the permissiveness of human keratinocytes to HTNV infection.

[Construction and identification of luciferase and EGFP expression vectors containing human IFN-ß promoter].

OBJECTIVE: To construct a luciferase expression vector (pGL3-IFNB1) and an enhanced green fluorescent protein expression vector (pGE3-IFNB1) containing human IFN-ß promoter, and verify the promoter activity of IFN-ß in A549 cells. METHODS: IFN-ß promoter was amplified with the human genome DNA by PCR, then the segment was cloned into the eukaryotic expression vectors pGL3-basic and pGE3-basic by PCR. The eukaryotic expression vectors were named pGL3-IFNB1 and pGE3-IFNB1, respectively. The recombinant vectors were then transiently transfected into A549 cells respectively, and 6 hours later, the transfected cells were infected with Hantaan virus (HTNV). After 24 hours, the expressions of pGL3-IFNB1 and pGE3-IFNB1 were tested in A549 cells. RESULTS: Double restriction enzyme digestion and sequence analysis showed that the recombinant vectors were successfully constructed and expressed in A549 cells correctly. After HTNV infection, stronger expression was observed in these cells. CONCLUSION: The recombinant vectors pGL3-IFNB1 and pGE3-IFNB1 containing IFN-ß promoter have been successfully constructed. It provides useful tools for further study on the mechanism of IFN-ß production induced by virus.