Heme Oxygenase-1 suppresses duck Tembusu virus replication in vitro

CDK5-mediated rearrangement of vimentin during Duck Tembusu virus infection inhibits viral replication

Duck Tembusu virus (DTMUV) is a newly emerging pathogen that causes massive economic losses to the poultry industry in China and neighbouring countries. Vimentin, an intermediate filament protein, has been demonstrated to be involved in viral replication during infection. However, the specific role of vimentin in DTMUV replication has not been determined. In this study, we found that overexpression of vimentin in BHK-21 cells can inhibit DTMUV replication. Moreover, DTMUV replication was enhanced after vimentin expression was reduced in BHK-21 cells via small interfering RNA (siRNA). Further research indicated that DTMUV infection had no effect on the transcription or expression of vimentin. However, we found that DTMUV infection induced vimentin rearrangement, and the rearrangement of vimentin was subsequently confirmed to negatively modulate viral replication through the use of a vimentin network disrupting agent. Vimentin rearrangement is closely associated with its phosphorylation. Our experiments revealed that the phosphorylation of vimentin at Ser56 was promoted in the early stage of DTMUV infection. In addition, by inhibiting the phosphorylation of vimentin at Ser56 with a CDK5 inhibitor, vimentin rearrangement was suppressed, and DTMUV replication was significantly enhanced. These results indicated that DTMUV infection induced vimentin phosphorylation and rearrangement through CDK5, resulting in the inhibition of DTMUV replication. In summary, our study reveals a role for vimentin as a negative factor in the process of DTMUV replication, which helps to elucidate the function of cellular proteins in regulating DTMUV replication.

Heme oxygenase-1 is an equid alphaherpesvirus 8 replication restriction host protein and suppresses viral replication via the PKCβ/ERK1/ERK2 and NO/cGMP/PKG pathway

Equid alphaherpesvirus 8 (EqHV-8) is one of the most economically important viruses that is known to cause severe respiratory disease, abortion, and neurological syndromes in equines. However, no effective vaccines or therapeutic agents are available to control EqHV-8 infection. Heme oxygenase-1 (HO-1) is an antioxidant defense enzyme that displays significant cytoprotective effects against different viral infections. However, the literature on the function of HO-1 during EqHV-8 infection is little. We explored the effects of HO-1 on EqHV-8 infection and revealed its potential mechanisms. Our results demonstrated that HO-1 induced by cobalt-protoporphyrin (CoPP) or HO-1 overexpression inhibited EqHV-8 replication in susceptible cells. In contrast, HO-1 inhibitor (zinc protoporphyria) or siRNA targeting HO-1 reversed the anti-EqHV-8 activity. Furthermore, biliverdin, a metabolic product of HO-1, mediated the anti-EqHV-8 effect of HO-1 via both the protein kinase C (PKC)β/extracellular signal-regulated kinase (ERK)1/ERK2 and nitric oxide (NO)-dependent cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG) signaling pathways. In addition, CoPP protected the mice by reducing the EqHV-8 infection in the lungs. Altogether, these results indicated that HO-1 can be developed as a promising therapeutic strategy to control EqHV-8 infection.IMPORTANCEEqHV-8 infections have threatened continuously donkey and horse industry worldwide, which induces huge economic losses every year. However, no effective vaccination strategies or drug against EqHV-8 infection until now. Our present study found that one host protien HO-1 restrict EqHV-8 replication in vitro and in vivo. Furthermore, we demonstrate that HO-1 and its metabolite biliverdin suppress EqHV-8 relication via the PKCβ/ERK1/ERK2 and NO/cGMP/PKG pathways. Hence, we believe that HO-1 can be developed as a promising therapeutic strategy to control EqHV-8 infection.

Mechanisms by which silencing long-stranded noncoding RNA KCNQ1OT1 alleviates myocardial ischemia/reperfusion injury (MI/RI)-induced cardiac injury via miR-377-3p/HMOX1

BACKGROUND

The key complication of myocardial infarction therapy is myocardial ischemia/reperfusion injury (MI/RI), and there is no effective treatment. The present study elucidates the mechanism of action of lncRNA KCNQ1OT1 in alleviating MI/RI and provides new perspectives and therapeutic targets for cardiac injury-related diseases.

METHODS

An ischemia/reperfusion (I/R) injury model of human adult cardiac myocytes (HACMs) was constructed, and the expression of KCNQ1OT1 and miR-377-3p was determined by RT‒qPCR. The levels of related proteins were detected by western blot analysis. Cell proliferation was detected by a CCK-8 assay, and cell apoptosis and ROS content were determined by flow cytometry. SOD and MDA expression as well as Fe2+ changes were detected by related analysis kits. The target binding relationships between lncRNA KCNQ1OT1 and miR-377-3p as well as between miR-377-3p and heme oxygenase 1 (HMOX1) were verified by a dual-luciferase reporter gene assay.

RESULTS

Myocardial ischemia‒reperfusion caused oxidative stress in HACMs, resulting in elevated ROS levels, increased Fe2+ levels, decreased cell viability, and increased LDH release (a marker of myocardial injury), and apoptosis. KCNQ1OT1 and HMOX1 were upregulated in I/R-induced myocardial injury, but the level of miR-377-3p was decreased. A dual-luciferase reporter gene assay indicated that lncRNA KCNQ1OT1 targets miR-377-3p and that miR-377-3p targets HMOX1. Inhibition of HMOX1 alleviated miR-377-3p downregulation-induced myocardial injury. Furthermore, lncRNA KCNQ1OT1 promoted the level of HMOX1 by binding to miR-377-3p and aggravated myocardial injury.

CONCLUSION

LncRNA KCNQ1OT1 aggravates ischemia‒reperfusion-induced cardiac injury via miR-377-3P/HMOX1.

Cobalt Protoporphyrin Blocks EqHV-8 Infection via IFN-α/β Production

Equid alphaherpesvirus type 8 (EqHV-8) is the causative agent of severe respiratory disease, abortions, and neurological syndromes in equines and has resulted in huge economic losses to the donkey industry. Currently, there exist no therapeutic molecules for controlling EqHV-8 infection. We evaluated the potential antiviral activity of cobalt protoporphyrin (CoPP) against EqHV-8 infection. Our results demonstrated that CoPP inhibited EqHV-8 infection in susceptible cells and mouse models. Furthermore, CoPP blocked the replication of EqHV-8 via HO-1 (heme oxygenase-1) mediated type I interferon (IFN) response. In conclusion, our data suggested that CoPP could serve as a novel potential molecule to develop an effective therapeutic strategy for EqHV-8 prevention and control.

Brucella induces heme oxygenase-1 expression to promote its infection

Brucellosis is a zoonotic and contagious infectious disease caused by Brucella spp, which causes substantial economic losses to animal husbandry and leads to severe public health problems. Brucella have evolved multiple strategies to escape host immunity and survive within host cells. Elucidating the immune evasion strategies during Brucella infection will facilitate the control of brucellosis. The host enzyme, heme oxygenase-1 (HO-1), is a multifunctional protein that functions during inflammatory diseases and microbial infections. However, how HO-1 functions during Brucella infection is rarely studied. In this study, we evaluated the role of HO-1 during Brucella infection. We found that Brucella infection induced HO-1 expression in macrophages. We further showed that HO-1 was regulated by PI3K, AMPK kinase, and nuclear erythroid-related factor 2 (Nrf2) in macrophages. Interestingly, knocking out HO-1 or inhibiting the activity of HO-1 significantly decreased Brucella intracellular growth. Inducing the expression of HO-1 by treatment with CoPP promoted Brucella intracellular growth. Mechanistic analyses indicated that the effect of HO-1 was not meditated by HO-1 metabolites, but by decreasing the production of reactive oxygen species (ROS), TNF-α, and IL-1β. Moreover, Brucella induced HO-1 expression in bone marrow-derived macrophages (BMDMs) and mice. When the expression of HO-1 was knocked down in BMDMs, the intracellular survival of Brucella was reduced. Furthermore, the induction of HO-1 by CoPP significantly increased bacterial loads in vivo. Thus, we demonstrated that Brucella induced HO-1 expression to promote its survival and growth in vitro and in vivo. This study also identified HO-1 as a novel innate immune evasion factor during Brucella infection.