Fujun Jin

Heat-Shock Protein 90 Promotes Nuclear Transport of Herpes Simplex Virus 1 Capsid Protein by Interacting with Acetylated Tubulin

Although it is known that inhibitors of heat shock protein 90 (Hsp90) can inhibit herpes simplex virus type 1 (HSV-1) infection, the role of Hsp90 in HSV-1 entry and the antiviral mechanisms of Hsp90 inhibitors remain unclear. In this study, we found that Hsp90 inhibitors have potent antiviral activity against standard or drug-resistant HSV-1 strains and viral gene and protein synthesis are inhibited in an early phase. More detailed studies demonstrated that Hsp90 is upregulated by virus entry and it interacts with virus. Hsp90 knockdown by siRNA or treatment with Hsp90 inhibitors significantly inhibited the nuclear transport of viral capsid protein (ICP5) at the early stage of HSV-1 infection. In contrast, overexpression of Hsp90 restored the nuclear transport that was prevented by the Hsp90 inhibitors, suggesting that Hsp90 is required for nuclear transport of viral capsid protein. Furthermore, HSV-1 infection enhanced acetylation of α-tubulin and Hsp90 interacted with the acetylated α-tubulin, which is suppressed by Hsp90 inhibition. These results demonstrate that Hsp90, by interacting with acetylated α-tubulin, plays a crucial role in viral capsid protein nuclear transport and may provide novel insight into the role of Hsp90 in HSV-1 infection and offer a promising strategy to overcome drug-resistance.

Inhibition of herpes simplex virus type 1 entry by chloride channel inhibitors tamoxifen and NPPB

Herpes simplex virus type 1 (HSV-1) infection is very common worldwide and can cause significant health problems from periodic skin and corneal lesions to encephalitis. Appearance of drug-resistant viruses in clinical therapy has made exploring novel antiviral agents emergent. Here we show that chloride channel inhibitors, including tamoxifen and 5-nitro-2-(3-phenyl-propylamino) benzoic acid (NPPB), exhibited extensive antiviral activities toward HSV-1 and ACV-resistant HSV viruses. HSV-1 infection induced chloride ion influx while treatment with inhibitors reduced the increase of intracellular chloride ion concentration. Pretreatment or treatment of inhibitors at different time points during HSV-1 infection all suppressed viral RNA synthesis, protein expression and virus production. More detailed studies demonstrated that tamoxifen and NPPB acted as potent inhibitors of HSV-1 early entry step by preventing viral binding, penetration and nuclear translocation. Specifically the compounds appeared to affect viral fusion process by inhibiting virus binding to lipid rafts and interrupting calcium homeostasis. Taken together, the observation that tamoxifen and NPPB can block viral entry suggests a stronger potential for these compounds as well as other ion channel inhibitors in antiviral therapy against HSV-1, especially the compound tamoxifen is an immediately actionable drug that can be reused for treatment of HSV-1 infections.

In vitro and in vivo anti-inflammatory effects of theaflavin-3,3′-digallate on lipopolysaccharide-induced inflammation

&NA; Inflammation is a defensive response against various harmful stimuli and stress conditions, such as tissue injury and one of the most common pathological processes occurring in human diseases. Theaflavin‐3,3′‐digallate, one of the theaflavins present in black tea, exhibits several bioactive properties, including the ability to lower the incidence of coronary heart disease, a positive effect on the bone mineral density, and the ability to prevent cancer. The aim of this study was to evaluate whether theaflavin‐3,3′‐digallate could reduce the production of pro‐inflammatory cytokines in vivo and in vitro and ameliorate acute lung injury (ALI) in a mouse model. In this study, we demonstrated that theaflavin‐3,3′‐digallate suppressed the lipopolysaccharide (LPS)‐induced phosphorylation of c‐Jun N‐terminal kinase and p38 mitogen‐activated protein kinase in RAW 264.7 macrophages. In addition, we also showed that theaflavin‐3,3′‐digallate inhibited the expression of tumor necrosis factor alpha, interleukin ‐1 beta, and interleukin 6 in phorbol myristate acetate ‐primed U937 and RAW 264.7 cells. Furthermore, theaflavin‐3,3′‐digallate treatment attenuated the severity of LPS‐induced ALI in mice. These results suggested that theaflavin‐3,3′‐digallate might be a potential therapeutic candidate for the treatment of inflammation and inflammatory diseases.

Silencing Herpes Simplex Virus Type 1 Capsid Protein Encoding Genes by siRNA: A Promising Antiviral Therapeutic Approach

Herpes simplex virus type 1 (HSV-1), a member of the herpesviridae, causes a variety of human viral diseases globally. Although a series of antiviral drugs are available for the treatment of infection and suppression of dissemination, HSV-1 remains highly prevalent worldwide. Therefore, the development of novel antiviral agents with different mechanisms of action is a matter of extreme urgency. During the proliferation of HSV-1, capsid assembly is essential for viral growth, and it is highly conserved in all HSV-1 strains. In this study, small interfering RNAs (siRNAs) against the HSV-1 capsid protein were screened to explore the influence of silencing capsid expression on the replication of HSV-1. We designed and chemically synthesized siRNAs for the capsid gene and assessed their inhibitory effects on the expression of target mRNA and the total intracellular viral genome loads by quantitative real-time PCR, as well as on the replication of HSV-1 via plaque reduction assays and electron microscopy. Our results showed that siRNA was an effective approach to inhibit the expression of capsid protein encoding genes including UL18, UL19, UL26, UL26.5, UL35 and UL38 in vitro. Interference of capsid proteins VP23 (UL18) and VP5 (UL19) individually or jointly greatly affected the replication of clinically isolated acyclovir-resistant HSV-1 as well as HSV-1/F and HSV-2/333. Plaque numbers and intracellular virions were significantly reduced by simultaneous knockdown of UL18 and UL19. The total intracellular viral genome loads were also significantly decreased in the UL18 and UL19 knockdown groups compared with the viral control. In conclusion, interfering with UL18 and UL19 gene expression could inhibit HSV-1 replication efficiently in vitro. Our research offers new targets for an RNA interference-based therapeutic strategy against HSV-1.

Apoptosis inhibition effect of Dihydromyricetin against UVA-exposed human keratinocyte cell line

UVA irradiation stimulates the production of reactive oxygen species (ROS), which results in oxidative stress, cellular damage, and ultimately, cell death by interacting with other intracellular molecules. In the present study, we explored the protective role of Dihydromyricetin (DHM,1.25-10μM) against UVA-induced inflammation response and apoptosis in the human keratinocyte cell line (HaCaT cells) and the underlying mechanisms. DHM pre-treatment significantly increased HaCaT cell viability and suppressed UVA-induced production of inflammatory cytokines, as well as apoptosis of HaCaT cells. Moreover, DHM pre-treatment prohibited UVA-induced ROS generation, mitochondrial membrane potential decrease, and the phosphorylation of histone H2AX(γ-H2AX), a sensitive biomarker for DNA damage. Meanwhile, DHM could enhance GSH-Px activity and decrease the content of MDA in UVA ray treated HaCaT cells. Notably, the anti-apoptotic potential of DHM was correlated with an increased expression of anti-apoptotic proteins (Bcl-2 and Bcl-xl) and decreased expression of pro-apoptotic proteins (Bax), as well as the inhibition of caspase proteins activation. Additionally, DHM treatment also prevented the nuclear translocation of NF-κB/p65 and the phosphorylation of c-Jun. N-terminal kinase (JNK), which is an upstream modulator of NF-κB/p65. Therefore, DHM may be potentially useful in the prevention of UVA-induced skin damage.

Pentagalloylglucose Blocks the Nuclear Transport and the Process of Nucleocapsid Egress to Inhibit HSV-1 Infection.

Herpes simplex virus type 1 (HSV-1), a widespread virus, causes a variety of human viral diseases worldwide. The serious threat of drug-resistance highlights the extreme urgency to develop novel antiviral drugs with different mechanisms of action. Pentagalloylglucose (PGG) is a natural polyphenolic compound with significant anti-HSV activity; however, the mechanisms underlying its antiviral activity need to be defined by further studies. In this study, we found that PGG treatment delays the nuclear transport process of HSV-1 particles by inhibiting the upregulation of dynein (a cellular major motor protein) induced by HSV-1 infection. Furthermore, PGG treatment affects the nucleocapsid egress of HSV-1 by inhibiting the expression and disrupting the cellular localization of pEGFP-UL31 and pEGFP-UL34, which are indispensable for HSV-1 nucleocapsid egress from the nucleus. However, the over-expression of pEGFP-UL31 and pEGFP-UL34 could decrease the antiviral effect of PGG. In this study, for the first time, the antiviral activity of PGG against acyclovir-resistant virus was demonstrated in vitro, and the possible mechanisms of its anti-HSV activities were identified based on the inhibition of nuclear transport and nucleocapsid egress in HSV-1. It was further confirmed that PGG could be a promising candidate for HSV therapy, especially for drug-resistant strains.

Long-Term Survival of AIDS Patients Treated with Only Traditional Chinese Medicine

Abstract Traditional Chinese herbal medicine (TCM) has been used in Chinese society for more than 5,000 years to treat diseases from inflammation to cancer. Here, we report the case of nine living AIDS patients in the age range of 51 to 67 who were treated with either a unique formula of TCM alone from 2001 to 2009 or the TCM from 2001 to 2006 and then switched to occasional antiretroviral therapy. Surprisingly, the viral loads of eight patients were at undetectable levels on June 28, 2016, while the remaining patient had a low viral load of 29 copies/ml. The CD4+ counts (170–592 cells/μl) and CD4+/CD8+ ratios (0.21–0.90) of the nine patients are excellent, contributing to their current good health. Thus, the case study suggests that the TCM has the potential to become a functional cure for HIV/AIDS.

O-acylation of chitosan nanofibers by short-chain and long-chain fatty acids

Chitosan nanofibers (CSNFs) have potential applications in biomaterials, oil recovery and food packaging, but their instability in moist environment has limited their full utilization. Here we report that CSNFs can be O-acylated in a post-electrospinning treatment by using pyridine as catalyst and short-chain (C2, C3, C4, C5 and C6) and long-chain (C8 and C12) fatty acid anhydrates as acylation agents. The effects of O-acylation to CSNFs were analyzed in detail. FT-IR, 1H NMR and elemental analysis indicated that the hydroxyl groups of chitosan in CSNFs were acylated in 2h. XRD spectra indicated that the O-acylation modification altered the crystal structure of the native fibers and the acyl substituents packed in a laterally aligned and layered structure. SEM examinations showed that the acylation modification could effectively control the fibrous structure of CSNFs and improve their stability in moist environment. The O-acylated CSNFs generally have an average diameter about 100nm except for laurelated CSNFs (∼200nm). Water contact angle measurement indicated that the wetting properties of O-acylated CSNFs were affected by the length of acyl side chains. This fiber acylation strategy can tune the material properties of CSNFs and expand their potential applications.

HSP90: a promising broad-spectrum antiviral drug target

The emergence of antiviral drug-resistant mutants is the most important issue in current antiviral therapy. As obligate parasites, viruses require host factors for efficient replication. An ideal therapeutic target to prevent drug-resistance development is represented by host factors that are crucial for the viral life cycle. Recent studies have indicated that heat shock protein 90 (HSP90) is a crucial host factor that is required by many viruses for multiple phases of their life cycle including viral entry, nuclear import, transcription, and replication. In this review, we summarize the most recent advances regarding HSP90 function, mechanisms of action, and molecular pathways that are associated with viral infection, and provide a comprehensive understanding of the role of HSP90 in the immune response and exosome-mediated viral transmission. In addition, several HSP90 inhibitors have entered clinical trials for specific cancers that are associated with viral infection, which further implies a crucial role for HSP90 in the malignant transformation of virus-infected cells; as such, HSP90 inhibitors exhibit excellent therapeutic potential. Finally, we describe the challenge of developing HSP90 inhibitors as anti-viral drugs.

Anti-herpes simplex virus activity of polysaccharides from Eucheuma gelatinae

Abstract Acyclovir is a commonly-used drug for treating herpes simplex virus (HSV) infections, but with its wide clinical application, more and more resistant strains have been found. Therefore, seeking a drug that can act against acyclovir-resistant virus has become an important goal of drug screening and development. In this study, plaque reduction assay, real-time PCR, Western blot, and immunofluorescence technique were used to investigate the antiviral effect of Eucheuma gelatinae polysaccharide (EGP) on HSV and to preliminarily clarify the in vitro anti-HSV mechanism of EGP. EGP was found to significantly inhibit HSV infection in vitro and displayed a good inhibitory effect on acyclovir-resistant strains. More detailed experiments have shown that EGP prevented early HSV-1 infection through directly inactivating HSV-1 particles and impairing virus attachment, but without effect on viral penetration. EGP also inhibited the RNA synthesis of HSV-1 early gene and late gene as well as viral DNA replication; no effect on immediate-early gene synthesis was observed. Besides, through immunofluorescence and western blot, we found that EGP significantly affected the protein synthesis of HSV-1. Taken together, these results demonstrate that EGP exerts its anti-HSV activity mainly through impeding early HSV-1 infection and inhibiting viral RNA and DNA syntheses. The weak cytotoxicity, strong viral inactivation as well as attachment inhibition activity enable EGP to be a virucide candidate for HSV therapy, especially for drug-resistant strains.