PEP-sNASP Peptide Alleviates LPS-Induced Acute Lung Injury Through the TLR4/TRAF6 Axis

Acute lung injury (ALI) is a severe inflammatory lung disease associated with macrophages. Somatic nuclear autoantigenic sperm protein (sNASP) is a negative regulator of Toll-like receptor (TLR) signaling that targets tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) in macrophages, which is required to maintain homeostasis of the innate immune response. In the present study, we generated a cell permeable PEP-sNASP peptide using the sNASP protein N-terminal domain, and examined its potential therapeutic effect in a mouse model of ALI induced by the intranasal administration of lipopolysaccharide (LPS) and elucidated the underlying molecular mechanisms in RAW 264.7 cells. In vivo, PEP-sNASP peptide treatment markedly ameliorated pathological injury, reduced the wet/dry (W/D) weight ratio of the lungs and the production of proinflammatory cytokines (interleukin (IL)-1β, IL-6, and TNF-α). In vitro, we demonstrated that when the PEP-sNASP peptide was transduced into RAW 264.7 cells, it bound to TRAF6, which markedly decreased LPS-induced proinflammatory cytokines by inhibiting TRAF6 autoubiquitination, nuclear factor (NF)-κB activation, reactive oxygen species (ROS) and cellular nitric oxide (NO) levels. Furthermore, the PEP-sNASP peptide also inhibited NLR family pyrin domain containing 3 (NLRP3) inflammasome activation. Our results therefore suggest that the PEP-sNASP may provide a potential protein therapy against oxidative stress and pulmonary inflammation via selective TRAF6 signaling.

Effect of respiratory syncytial virus on the growth of hepatocellular carcinoma cell-lines

In several reports, the respiratory syncytial virus (RSV) was identified as an oncolytic virus in cancer cells (e.g., lung and prostate cancer). However, the effects of RSV in hepatocellular carcinoma (HCC) cells have not yet been investigated. Here, we observed the inhibitory effects of RSV infection in HCC cell-lines. Cell growth was significantly decreased by RSV infection in BNL-HCC, Hep3B, Huh-7 and SNU-739 cells. After RSV infection, plaque formation and syncytial formation were observed in affected Hep3B and Huh-7 cells. RSV protein-expression was also detected in Hep3B and Huh-7 cells; however, only Huh-7 cells showed apoptosis after RSV infection. Furthermore, inhibition of cell migration by RSV infection was observed in BNL-HCC, Hep3B, Huh-7 and SNU-739 cells. Therefore, further investigation is required to clarify the molecular mechanism of RSV-mediated inhibition of HCC cell growth, and to develop potential RSV oncolytic viro-therapeutics. [BMB Reports 2015; 48(10): 565-570]

The efficacy of chimeric vaccines constructed with PEP-1 and Ii-Key linking to a hybrid epitope from heterologous viruses

The heterologous epitope-peptide from different viruses may represent an attractive candidate vaccine. In order to evaluate the role of cell-permeable peptide (PEP-1) and Ii-Key moiety from the invariant chain (Ii) of MHC on the heterologous peptide chimeras, we linked the two vehicles to hybrid epitopes on the VP2 protein (aa197-209) of the infectious bursal disease virus and HN protein (aa345-353) of the Newcastle disease virus. The chimeric vaccines were prepared and injected into mice. The immune effects were measured by indirect ELISA. The results showed that the vehicle(s) could significantly boost immune effects against the heterologous epitope peptide. The Ii-Key-only carrier induced more effective immunological responses, compared with the PEP-1 and Ii-Key hybrid vehicle. The carrier-peptide hybrids all showed strong colocalization with major histocompatibility complex (MHC) class II molecules compared with the epitope-peptide (weakly-binding) after co-transfection into 293T cells. Together, our results lay the groundwork for designing new hybrid vaccines based on Ii-Key and/or PEP-1 peptides.

PEP-1-HO-1 prevents MPTP-induced degeneration of dopaminergic neurons in a Parkinson's disease mouse model

Heme oxygenase-1 (HO-1) degrades heme to carbon dioxide, biliverdin, and Fe2+, which play important roles in various biochemical processes. In this study, we examined the protective function of HO-1 against oxidative stress in SH-SY5Y cells and in a Parkinson's disease mouse model. Western blot and fluorescence microscopy analysis demonstrated that PEP-1-HO-1, fused with a PEP-1 peptide can cross the cellular membranes of human neuroblastoma SH-SY5Y cells. In addition, the transduced PEP-1-HO-1 inhibited generation of reactive oxygen species (ROS) and cell death caused by 1-methyl-4-phenylpyridinium ion (MPP+). In contrast, HO-1, which has no ability to transduce into SH-SY5Y cells, failed to reduce MPP+-induced cellular toxicity and ROS production. Furthermore, intraperitoneal injected PEP-1-HO-1 crossed the blood-brain barrier in mouse brains. In a PD mouse model, PEP-1-HO-1 significantly protected against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced toxicity and dopaminergic neuronal death. Therefore, PEP-1-HO-1 could be a useful agent in treating oxidative stress induced ailments including PD.

Anti-inflammatory mechanisms of N-adamantyl-4-methylthiazol-2-amine in lipopolysaccharide-stimulated BV-2 microglial cells

The activation of microglia is crucially associated with the neurodegeneration observed in many neuroinflammatory pathologies, such as multiple sclerosis, Parkinson's disease, and Alzheimer's disease. We have examined various thiazole derivatives with the goal of developing new anti-neuroinflammatory drugs. Thiazole derivatives are attractive candidates for drug development, because they are efficiently synthesized and active against a number of disease organisms and conditions, including neurodegenerative disorders. The present study investigated the effects of a new compound, N-adamantyl-4-methylthiazol-2-amine (KHG26693), against lipopolysaccharide (LPS)-induced inflammation in cultured BV-2 microglial cells. KHG26693 suppressed several inflammatory responses in LPS-activated cells, as evidenced by decreased levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), hydrogen peroxide (H(2)O(2)), reactive oxygen species (ROS), nitric oxide (NO), and lipid peroxidation. These anti-inflammatory/antioxidative actions occurred as a result of the downregulation of NADPH oxidase (NOX), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) content, but not as a result of the upregulation of superoxide dismutase (SOD) or catalase activity. The pharmacological properties of KHG26693 were also facilitated via inhibition of both the cluster of differentiation 14 (CD14)/toll-like receptor 4 (TLR4)-dependent nuclear factor kappa B (NF-κB) signaling pathway and extracellular signal-regulated kinase (ERK) phosphorylation. Furthermore, KHG26693 successfully blocked the migration of LPS-activated microglia, most likely by modulating the ERK pathway. Taken together, these results demonstrate that the anti-inflammatory and antioxidative actions of KHG26693 are mediated, at least in part, through the control of microglial activation.

Neuroprotective effect of PEP-1-peroxiredoxin2 on CA1 regions in the hippocampus against ischemic insult

BACKGROUND

Oxidative stress is a leading cause of various diseases, including ischemia and inflammation. Peroxiredoxin2 (PRX2) is one of six mammalian isoenzymes (PRX1-6) that can reduce hydrogen peroxide (H2O2) and organic hydroperoxides to water and alcohols.

METHODS

We produced PEP-1-PRX2 transduction domain (PTD)-fused protein and investigated the effect of PEP-1-PRX2 on oxidative stress-induced neuronal cell death by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Western blot, immunofluorescence microscopy, and immunohistochemical analysis.

RESULTS

Our data showed that PEP-1-PRX2, which can effectively transduce into various types of cells and brain tissues, could be implicated in suppressing generation of reactive oxygen species, preventing depolarization of the mitochondrial membrane, and inhibiting the apoptosis pathway in H2O2-stimulated HT22, murine hippocampal neuronal cells, likely resulting in protection of HT22 cells against H2O2-induced toxicity. In addition, we found that in a transient forebrain ischemia model, PEP-1-PRX2 inhibited the activation of astrocytes and microglia in the CA1 region of the hippocampus and lipid peroxidation and also prevented neuronal cell death against ischemic damage.

CONCLUSIONS

These findings suggest that the transduced PEP-1-PRX2 has neuroprotective functions against oxidative stress-induced cell death in vitro and in vivo.

GENERAL SIGNIFICANCE

PEP-1-PRX2 could be a potential therapeutic agent for oxidative stress-induced brain diseases such as ischemia.

Tat-fused recombinant human SAG prevents dopaminergic neurodegeneration in a MPTP-induced Parkinson's disease model

Excessive reactive oxygen species (ROS) generated from abnormal cellular process lead to various human diseases such as inflammation, ischemia, and Parkinson's disease (PD). Sensitive to apoptosis gene (SAG), a RING-FINGER protein, has anti-apoptotic activity and anti-oxidant activity. In this study, we investigate whether Tat-SAG, fused with a Tat domain, could protect SH-SY5Y neuroblastoma cells against 1-methyl-4-phenylpyridinium (MPP(+)) and dopaminergic (DA) neurons in the substantia nigra (SN) against 1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine (MPTP) toxicity. Western blot and immunohistochemical analysis showed that, unlike SAG, Tat-SAG transduced efficiently into SH-SY5Y cells and into the brain, respectively. Tat-SAG remarkably suppressed ROS generation, DNA damage, and the progression of apoptosis, caused by MPP(+) in SH-SY5Y cells. Also, immunohistochemical data using a tyrosine hydroxylase antibody and cresyl violet staining demonstrated that Tat-SAG obviously protected DA neurons in the SN against MPTP toxicity in a PD mouse model. Tat-SAG-treated mice showed significant enhanced motor activities, compared to SAG- or Tat-treated mice. Therefore, our results suggest that Tat-SAG has potential as a therapeutic agent against ROS-related diseases such as PD.

Tat-glyoxalase protein inhibits against ischemic neuronal cell damage and ameliorates ischemic injury

Methylglyoxal (MG), a metabolite of glucose, is the major precursor of protein glycation and induces apoptosis. MG is associated with neurodegeneration, including oxidative stress and impaired glucose metabolism, and is efficiently metabolized to S-D-lactoylglutathione by glyoxalase (GLO). Although GLO has been implicated as being crucial in various diseases including ischemia, its detailed functions remain unclear. Therefore, we investigated the protective effect of GLO (GLO1 and GLO2) in neuronal cells and an animal ischemia model using Tat-GLO proteins. Purified Tat-GLO protein efficiently transduced into HT-22 neuronal cells and protected cells against MG- and H2O2-induced cell death, DNA fragmentation, and activation of caspase-3 and mitogen-activated protein kinase. In addition, transduced Tat-GLO protein increased D-lactate in MG- and H2O2-treated cells whereas glycation end products (AGE) and MG levels were significantly reduced in the same cells. Gerbils treated with Tat-GLO proteins displayed delayed neuronal cell death in the CA1 region of the hippocampus compared with a control. Furthermore, the combined neuroprotective effects of Tat-GLO1 and Tat-GLO2 proteins against ischemic damage were significantly higher than those of each individual protein. Those results demonstrate that transduced Tat-GLO protein protects neuronal cells by inhibiting MG- and H2O2-mediated cytotoxicity in vitro and in vivo. Therefore, we suggest that Tat-GLO proteins could be useful as a therapeutic agent for various human diseases related to oxidative stress including brain diseases.

PEP-1-PON1 protein regulates inflammatory response in raw 264.7 macrophages and ameliorates inflammation in a TPA-induced animal model

Paraoxonase 1 (PON1) is an antioxidant enzyme which plays a central role in various diseases. However, the mechanism and function of PON1 protein in inflammation are poorly understood. Since PON1 protein alone cannot be delivered into cells, we generated a cell permeable PEP-1-PON1 protein using protein transduction domains, and examined whether it can protect against cell death in lipopolysaccharide (LPS) or hydrogen peroxide (H₂O₂)-treated Raw 264.7 cells as well as mice with 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced skin inflammation. We demonstrated that PEP-1-PON1 protein transduced into Raw 264.7 cells and markedly protected against LPS or H₂O₂-induced cell death by inhibiting cellular reactive oxygen species (ROS) levels, the inflammatory mediator’s expression, activation of mitogen-activated protein kinases (MAPKs) and cellular apoptosis. Furthermore, topically applied PEP-1-PON1 protein ameliorates TPA-treated mice skin inflammation via a reduction of inflammatory response. Our results indicate that PEP-1-PON1 protein plays a key role in inflammation and oxidative stress in vitro and in vivo. Therefore, we suggest that PEP-1-PON1 protein may provide a potential protein therapy against oxidative stress and inflammation.

PEP-1-PEA-15 protects against toxin-induced neuronal damage in a mouse model of Parkinson's disease

BACKGROUND

PEA-15 is abundantly expressed in both neurons and astrocytes throughout the brain. It is a multifunctional protein with the ability to increase cell survival via anti-apoptotic and anti-proliferative properties. However, the function of PEA-15 in neuronal diseases such as Parkinson's disease (PD) remains unclear. In this study, we investigated the protective effects of PEA-15 on neuronal damage induced by MPP(+) in neuroblastoma SH-SY5Y and BV2 microglia cells and in a MPTP-induced PD mouse model using cell-permeable PEP-1-PEA-15.

METHODS

PEP-1-PEA-15 was purified using affinity chromatography. Cell viability and DNA fragmentation were examined by MTT assay and TUNEL staining. Dopaminergic neuronal cell death in the animal model was examined by immunohistochemistry.

RESULTS

PEP-1-PEA-15 transduced into the SH-SY5Y and BV2 cells in a time- and dose-dependent manner. Transduced PEP-1-PEA-15 protected against MPP(+)-induced toxicity by inhibiting intracellular ROS levels and DNA fragmentation. Further, it enhanced the expression levels of Bcl-2 and caspase-3 while reducing the expression levels of Bax and cleaved caspase-3. We found that PEP-1-PEA-15 transduced into the substantia nigra and prevented dopaminergic neuronal cell death in a MPTP-induced PD mouse. Also, we showed the neuroprotective effects in the model by demonstrating that treatment with PEP-1-PEA-15 ameliorated MPTP-induced behavioral dysfunctions and increased dopamine levels in the striatum.

CONCLUSIONS

PEP-1-PEA-15 can efficiently transduce into cells and protects against neurotoxin-induced neuronal cell death in vitro and in vivo.

GENERAL SIGNIFICANCE

These results demonstrate the potential for PEP-1-PEA-15 to provide a new strategy for protein therapy treatment of a variety of neurodegenerative diseases including PD.

PEP-1-SIRT2 inhibits inflammatory response and oxidative stress-induced cell death via expression of antioxidant enzymes in murine macrophages

Sirtuin 2 (SIRT2), a member of the sirtuin family of proteins, plays an important role in cell survival. However, the biological function of SIRT2 protein is unclear with respect to inflammation and oxidative stress. In this study, we examined the protective effects of SIRT2 on inflammation and oxidative stress-induced cell damage using a cell permeative PEP-1-SIRT2 protein. Purified PEP-1-SIRT2 was transduced into RAW 264.7 cells in a time- and dose-dependent manner and protected against lipopolysaccharide- and hydrogen peroxide (H₂O₂)-induced cell death and cytotoxicity. Also, transduced PEP-1-SIRT2 significantly inhibited the expression of cytokines as well as the activation of NF-κB and mitogen-activated protein kinases (MAPKs). In addition, PEP-1-SIRT2 decreased cellular levels of reactive oxygen species (ROS) and of cleaved caspase-3, whereas it elevated the expression of antioxidant enzymes such as MnSOD, catalase, and glutathione peroxidase. Furthermore, topical application of PEP-1-SIRT2 to 12-O-tetradecanoylphorbol 13-acetate-treated mouse ears markedly inhibited expression levels of COX-2 and proinflammatory cytokines as well as the activation of NF-κB and MAPKs. These results demonstrate that PEP-1-SIRT2 inhibits inflammation and oxidative stress by reducing the levels of expression of cytokines and ROS, suggesting that PEP-1-SIRT2 may be a potential therapeutic agent for various disorders related to ROS, including skin inflammation.

PEP-1-ribosomal protein S3 protects dopaminergic neurons in an MPTP-induced Parkinson's disease mouse model

Parkinson's disease (PD) is a neurodegenerative disease characterized by a gradual loss of dopaminergic (DA) neurons in the substantia nigra (SN) of the brain. Ribosomal protein S3 (rpS3) has multiple functions related to protein synthesis, antioxidative activity, and UV endonuclease III activity. We have previously shown that PEP-1-rpS3 inhibits skin inflammation and provides neuroprotection against experimental cerebral ischemic damage. In this study, we examined whether PEP-1-rpS3 can protect DA neurons against oxidative stress in SH-SY5Y neuroblastoma cells and in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model. PEP-1-rpS3 was efficiently delivered to SH-SY5Y cells and the SN of the brain as confirmed by Western blot and immunohistochemical analysis. PEP-1-rpS3 significantly inhibited reactive oxygen species generation and DNA fragmentation induced by 1-methyl-4-phenylpyridinium, consequently leading to the survival of SH-SY5Y cells. The neuroprotection was related to the antiapoptotic activity of PEP-1-rpS3 that affected the levels of proapoptotic and antiapoptotic mediators. In addition, immunohistochemical data collected using a tyrosine hydroxylase antibody and cresyl violet staining demonstrated that PEP-1-rpS3 markedly protected DA cells in the SN against MPTP-induced oxidative stress. Therefore, our results suggest that PEP-1-rpS3 may be a potential therapy for PD.