Cell-permeable Tat-NBD peptide attenuates rat pancreatitis and acinus cell inflammation response

Development of a Decafluorobiphenyl Cyclized Peptide Targeting the NEMO-IKKα/β Interaction that Enhances Cell Penetration and Attenuates Lipopolysaccharide-Induced Acute Lung Injury

Aberrant canonical NF-κB signaling has been implicated in diseases, such as autoimmune disorders and cancer. Direct disruption of the interaction of NEMO and IKKα/β has been developed as a novel way to inhibit the overactivation of NF-κB. Peptides are a potential solution for disrupting protein-protein interactions (PPIs); however, they typically suffer from poor stability in vivo and limited tissue penetration permeability, hampering their widespread use as new chemical biology tools and potential therapeutics. In this work, decafluorobiphenyl-cysteine SNAr chemistry, molecular modeling, and biological validation allowed the development of peptide PPI inhibitors. The resulting cyclic peptide specifically inhibited canonical NF-κB signaling in vitro and in vivo, and presented positive metabolic stability, anti-inflammatory effects, and low cytotoxicity. Importantly, our results also revealed that cyclic peptides had huge potential in acute lung injury (ALI) treatment, and confirmed the role of the decafluorobiphenyl-based cyclization strategy in enhancing the biological activity of peptide NEMO-IKKα/β inhibitors. Moreover, it provided a promising method for the development of peptide-PPI inhibitors.

Potential of oligonucleotide- and protein/peptide-based therapeutics in the management of toxicant/stressor-induced diseases

Exposure to toxicants/stressors has been linked to the development of many human diseases. They could affect various cellular components, such as DNA, proteins, lipids, and non-coding RNAs (ncRNA), thereby triggering various cellular pathways, particularly oxidative stress, inflammatory responses, and apoptosis, which can contribute to pathophysiological states. Accordingly, modulation of these pathways has been the focus of numerous investigations for managing related diseases. The involvement of various ncRNAs, such as small interfering RNA (siRNA), microRNAs (miRNA), and long non-coding RNAs (lncRNA), as well as various proteins and peptides in mediating these pathways, provides many target sites for pharmaceutical intervention. In this regard, various oligonucleotide- and protein/peptide-based therapies have been developed to treat toxicity-induced diseases, which have shown promising results in vitro and in vivo. This comprehensive review provides information about various aspects of toxicity-related diseases including their causing factors, main underlying mechanisms and intermediates, and their roles in pathophysiological states. Particularly, it highlights the principles and mechanisms of oligonucleotide- and protein/peptide-based therapies in the treatment of toxicity-related diseases. Furthermore, various issues of oligonucleotides and proteins/peptides for clinical usage and potential solutions are discussed.

Cell-penetrating peptide-mediated delivery of therapeutic peptides/proteins to manage the diseases involving oxidative stress, inflammatory response and apoptosis

OBJECTIVES

Peptides and proteins represent great potential for modulating various cellular processes including oxidative stress, inflammatory response, apoptosis and consequently the treatment of related diseases. However, their therapeutic effects are limited by their inability to cross cellular barriers. Cell-penetrating peptides (CPPs), which can transport cargoes into the cell, could resolve this issue, as would be discussed in this review.

KEY FINDINGS

CPPs have been successfully exploited in vitro and in vivo for peptide/protein delivery to treat a wide range of diseases involving oxidative stress, inflammatory processes and apoptosis. Their in vivo applications are still limited due to some fundamental issues of CPPs, including nonspecificity, proteolytic instability, potential toxicity and immunogenicity.

SUMMARY

Totally, CPPs could potentially help to manage the diseases involving oxidative stress, inflammatory response and apoptosis by delivering peptides/proteins that could selectively reach proper intracellular targets. More studies to overcome related CPP limitations and confirm the efficacy and safety of this strategy are needed before their clinical usage.

Cell Permeable NBD Peptide-Modified Liposomes by Hyaluronic Acid Coating for the Synergistic Targeted Therapy of Metastatic Inflammatory Breast Cancer

Chronic inflammation is closely related to the development, deterioration, and metastasis of tumors. Recently, many studies have shown that down-regulating the expression of inflammation by blocking nuclear factor-κB (NF-κB) and signal transducer and activator of transcription 3 (STAT3) pathways could significantly inhibit tumor growth and metastasis. The combined application of curcumin (CUR) and celecoxib (CXB) has been proven to exert a synergistic antitumor effect via inhibiting the activation of NF-κB and STAT3. TAT-NBD (TN) peptide, a fusion peptide of NF-κB essential modulator (NEMO)-binding domain peptide (NBD) and cell-penetrating peptide (TAT), can selectively block NF-κB activating pathway resulting in tumor growth inhibition. In the present study, a novel TN-modified liposome coloading both CXB and CUR (TN-CCLP) at a synergistic ratio was first constructed with the property of synchronous release, then hyaluronic acid (HA) as CD44 targeting moiety was coated on the surface of the cationic liposome via electrostatic interaction to prepare the anionic HA/TN-CCLP. In vitro results of cytotoxicity, macrophage migration inhibition, and anti-inflammation efficacy revealed that TN-CCLP and HA/TN-CCLP were significantly superior to TN-LP and CCLP, while TN-CCLP exhibited better effects than HA/TN-CCLP due to higher cellular uptake ability. Different from in vitro data, after systematically treating 4T1 breast tumor-bearing mice, HA/TN-CCLP exerted the most striking effects on anti-inflammation, inhibition of macrophage recruitment, and antitumor because of the longest circulation time and maximum tumor accumulation. In particular, HA/TN-CCLP could availably block the lung metastasis of breast cancer. Taken together, the novel CD44 targeted TN-CCLP exhibited the potential for inhibiting tumor development and metastasis through improving inflammatory infiltration of tumor tissue.

Deoxycholic acid inhibited proliferation and induced apoptosis and necrosis by regulating the activity of transcription factors in rat pancreatic acinar cell line AR42J

The objective of this study is to investigate the effect of deoxycholic acid (DCA) on rat pancreatic acinar cell line AR42J and the functional mechanisms of DCA on AR42J cells. AR42J cells were treated with various concentrations of DCA for 24 h and also treated with 0.4 mmol/L DCA for multiple times, and then, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to detect the AR42J cell survival rate. Flow cytometric was used to detect the cell apoptosis and necrosis in AR42J cells treated with 0.4 mmol/L and 0.8 mmol/L DCA. The cells treated with phosphate buffer saline (PBS) were served as control. In addition, the DNA-binding activity assays of transcription factors (TFs) in nuclear proteins of cells treated with DCA were determined using Panomics Procarta Transcription Factor Assay Kit. The relative survival rates were markedly decreased (P < 0.05) in a dose- and time-dependent manner. Compared with control group, the cell apoptosis and necrosis ratio were both significantly elevated in 0.4 mmol/L DCA and 0.8 mmol/L DCA groups (P < 0.01). A significant increase (P < 0.05) in the activity of transcription factor 2 (ATF2), interferon-stimulated response element (ISRE), NKX-2.5, androgen receptor (AR), p53, and hypoxia-inducible factor-1 (HIF-1) was observed, and the activity of peroxisome proliferator-activated receptor (PPAR), activator protein 1 (AP1), and E2F1 was reduced (P < 0.05). In conclusion, DCA inhibited proliferation and induced apoptosis and necrosis in AR42J cells. The expression changes of related genes regulated by TFs might be the molecular mechanism of AR42J cell injury.

Determination of tissue levels of a neuroprotectant drug: the cell permeable JNK inhibitor peptide

INTRODUCTION

Cell permeable peptides (CPPs) represent a novel tool for the delivery of bioactive molecules into scarcely accessible organs, such as the brain. CPPs have been successfully used in pre-clinical studies for a variety of diseases, ranging from cancer to neurological disorders. However, the mechanisms by which CPPs cross biological membranes, as well as their pharmacokinetic properties, have been poorly explored due to the lack of specific and sensitive analytical methods.

METHODS

In this paper we describe a protocol to quantitatively determine the amount of CPPs in in vitro and in vivo experimental models. To this end we selected the peptide D-JNKI1 that was shown to prevent neurodegeneration in both acute and chronic degenerative disorders. This method allows an accurate quantitative analysis of D-JNKI1 in both neuronal lysates and tissue homogenates using mass spectrometry and stable isotope dilution approach.

RESULTS

We found that D-JNKI1 crosses cellular membranes with fast kinetics, through an active and passive mechanism. After acute intraperitoneal (ip) administration of D-JNKI1 in mice, the peptide was found in the main organs with particular regard to the liver and kidney. Interestingly, D-JNKI1 crosses the blood brain barrier (BBB) and reaches the brain, where it remains for one week.

DISCUSSION

The challenge lies in developing the clinical application of therapeutic cell permeable peptides. Discerning pharmacokinetic properties is a high priority to produce a powerful therapeutic strategy. Overall, our data shed light on the pharmacokinetic properties of D-JNKI1 and supports its powerful neuroprotective effect.

PTD-NBD polypeptide down-regulates expression of NF-κB p65 in inflammatory pancreatic acinar cell injury in rats

AIM: To examine the effect of PTD-NBD polypeptide on the expression of nuclear factor κB (NF-κB) p65 in inflammatory pancreatic acinar cell injury in rats.

METHODS: Rat pancreatic acinar cells were isolated, cultured, and divided into a normal control group, an acute pancreatitis (AP) group and a PTD-NBD polypeptides group. An in vitro model of AP was induced by treating rat pancreatic acinar cells with lipopolysaccharide (10 mg/L). Cell morphological changes were observed, and the contents of amylase, superoxide dismutase (SOD) and IL-1β in culture medium were tested. Expression of NF-κB p65 mRNA and protein in cells was detected by RT-PCR and Western blot 6 and 12 h after modeling, respectively.

RESULTS: Compared to the control group, pancreatic acinar cell swelling and death were increased (6 h: 8.9 ± 0.34 vs 1.1 ± 0.13; 12 h: 9.4 ± 0.26 vs 1.2 ± 0.15, both P < 0.05), the contents of amylase (6 h: 2135.8 ± 347.2 vs 873.5 ± 91.6; 12 h: 3299.6 ± 217.7 vs 917.7 ± 101.9, both P < 0.05) and IL-1β (6 h: 84.9 ± 15.7 vs 39.3 ± 7.9; 12 h: 95.6 ± 17.1 vs 38.9 ± 5.2, both P < 0.05) were increased and the contents of SOD were decreased in culture medium (6 h: 116.3 ± 30.3 vs 176.2 ± 21.6; 12 h: 101.5 ± 25.6 vs 173.6 ± 27.9, P < 0.05), and the expression of NF-κB p65 in pancreatic acinar cells was increased (P < 0.05) in the AP group at 6 and 12 h after modeling. Compared to the AP group, pancreatic acinar cell swelling and death were lessened (6 h: 6.8 ± 0.23 vs 8.9 ± 0.34; 12 h: 7.5 ± 0.19 vs 9.4 ± 0.26, both P < 0.05), the contents of SOD were raised (6 h: 137.6 ± 27.4 vs 116.3 ± 30.3; 12 h: 144.3 ± 23.6 vs 101.5 ± 25.6, both P < 0.05) and the contents of amylase (6 h: 1951.5 ± 211.7 vs 2135.8 ± 347.2; 12 h: 1761.3 ± 231.5 vs 3299.6 ± 217.7, both P < 0.05) and IL-1β (6 h: 66.8 ± 11.6 vs 84.9 ± 15.7; 12 h: 54.8 ± 21.2 vs 95.6 ± 17.1, both P < 0.05) were decreased in culture medium, and the expression of NF-κB p65 mRNA and protein was down-regulated in the PAT-NBD polypeptide group (P < 0.05).

CONCLUSION: PTD-NBD polypeptide can inhibit LPS-induced activation of NF-κB p65, down-regulate IL-1β expression and up-regulate SOD content, thereby reducing inflammatory pancreatic acinar cell injury.

Caffeic acid inhibits acute hyperhomocysteinemia-induced leukocyte rolling and adhesion in mouse cerebral venules

OBJECTIVE

To investigate the effects and possible mechanisms of CA on acute HHcy-induced leukocyte rolling and adhesion in mouse cerebral venules.

METHODS

Male C57 BL/6J mice were injected with DL-Hcy (50 mg/kg) and CA (10 mg/kg). The effect of CA on HHcy-induced leukocyte rolling and adhesion in cerebral vessels was assessed using intravital microscopy. Plasma cytokines and chemokines were evaluated by cytometric bead array. ROS production in HUVECs and adhesion molecule expression on leukocytes were determined by flow cytometry. E-selectin and ICAM-1 expression in cerebrovascular endothelium was detected by immunohistochemistry. CD18 phosphorylation and the Src/PI3K/Akt pathway in leukocytes were determined by confocal microscopy and Western blot.

RESULTS

CA inhibited HHcy-elicited leukocyte rolling and adhesion, decreased ROS production in HUVECs, and reduced plasma KC, MIP-2, and MCP-1 levels. CA reduced the E-selectin and ICAM-1 expression on cerebrovascular endothelium and CD11b/CD18 on leukocytes caused by HHcy. Of notice, CA depressed CD18 phosphorylation and the Src/PI3K/Akt pathway in leukocytes.

CONCLUSIONS

CA inhibited HHcy-provoked leukocyte rolling and adhesion in cerebral venules, ameliorating adhesion molecule expression and activation, which is related to the suppression of the Src/PI3K/Akt pathway in leukocytes.

Inhibitory kappa B Kinases as targets for pharmacological regulation

The inhibitory kappa B kinases (IKKs) are well recognized as key regulators of the nuclear factor kappa B (NF-κB) cascade and as such represent a point of convergence for many extracellular agents that activate this pathway. The IKKs generally serve to transduce pro-inflammatory and growth stimulating signals that contribute to major cellular processes but also play a key role in the pathogenesis of a number of human diseases. Therefore, the catalytic IKKs represent attractive targets for intervention with small molecule kinase inhibitors. IKK isoforms are assembled as variable multi-subunit IKK complexes that regulate not only NF-κB dimers, but also protein substrates out-with this cascade. Consequently, close consideration of how these individual complexes transduce extracellular signals and more importantly what impact small molecule inhibitors of the IKKs have on functional outcomes are demanded. A number of adenosine triphosphate (ATP)-competitive IKKβ-selective inhibitors have been developed but have demonstrated a lack of activity against IKKα. A number of these chemicals have also exhibited detrimental outcomes such as cellular toxicity and immuno-suppression. The impact of small molecule inhibitors of IKK catalytic activity will therefore be reappraised, examining the advantages and potential disadvantages to this type of intervention strategy in the treatment of diseases such as arthritis, intestinal inflammation and cancer. Furthermore, we will outline some emerging strategies, particularly the disruption of protein-protein interactions within the IKK complex, as an alternative route towards the development of novel pharmacological agents. Whether these alternatives may negate the limitations of ATP-competitive molecules and potentially avoid the issues of toxicity will be discussed.

NF-κB inhibition protects against tumor-induced cardiac atrophy in vivo

Cancer cachexia is a severe wasting syndrome characterized by the progressive loss of lean body mass and systemic inflammation. It occurs in approximately 80% of patients with advanced malignancy and is the cause of 20% to 30% of all cancer-related deaths. The mechanism by which striated muscle loss occurs is the tumor release of pro-inflammatory cytokines, such as IL-1, IL-6, and TNF-α. These cytokines interact with their cognate receptors on muscle cells to enhance NF-κB signaling, which then mediates muscle loss and significant cardiac dysfunction. Genetic inhibition of NF-κB signaling has demonstrated its predominant role in skeletal muscle loss. Therefore, we tested two novel drugs designed to specifically inhibit NF-κB by targeting the IκB kinase (IKK) complex: Compound A and NEMO binding domain (NBD) peptide. Using an established mouse model of cancer cachexia (C26 adenocarcinoma), we determined how these drugs affected the development of tumor-induced cardiac atrophy and function. Echocardiographic and histological analysis revealed that both Compound A and NBD inhibit cardiac NF-κB activity and prevent the development of tumor-induced systolic dysfunction and atrophy. This protection was independent of any effects of the tumor itself (Compound A) or tumor-secreted cytokines (NBD). This study identifies for the first time, to our knowledge, that drugs targeting the IKK complex are cardioprotective against cancer cachexia-induced cardiac atrophy and systolic dysfunction, suggesting therapies that may help reduce cardiac-associated morbidities found in patients with advanced malignancies.

The latest developments in synthetic peptides with immunoregulatory activities

In the past few years, many researches have provided us with much data demonstrating the abilities of synthetic peptides to impact immune response in vitro and in vivo. These peptides were designed according to the structure of some important protein molecules which play a key role in immune response, so they act with specific targets. The class I and II MHC-derived peptides inhibit the TCR recognition of antigen peptide-MHC complex. Rationally designed CD80 and CD154-binding peptides block the interaction between cell surface costimulatory molecules on antigen-presenting cells (APCs) and T cells. Some peptides were designed to inhibit the activities of cell signal proteins, including JNK, NF-κB and NFAT. Some peptide antagonists competitively bind to important cytokines and inhibit their activities, such as TNF-α, TGF-β and IL-1β inhibitory peptides. Adhesion molecule ICAM-1 derived peptides block the T cell adhesion and activation. These immunoregulatory peptides showed therapeutic effect in several animal models, including collagen-induced arthritis (CIA), autoimmune cystitis model, murine skin transplant model and cardiac allograft model. These results give us important implications for the development of a novel therapy for immune mediated diseases.

Cytotoxic effects of different bile acids on pancreatic acinar AR42J cells

AIM: To investigate the cytotoxic effects of seven different bile acids on pancreatic acinar AR42J cells by detecting the survival, necrosis and apoptosis of AR42J cells incubated with different bile acids.

METHODS: The effects of different bile acids on the survival of rat AR42J cells were detected by methyl thiazolyl tetrazolium (MTT) assay. Cell morphological changes were observed by microscopy and fluorescence microscopy. Cell apoptosis and necrosis were determined by annexin-V and propidium iodide double staining and flow cytometry.

RESULTS: Cholic acid (CA), glycocholic acid (GCA), and glycodeoxycholic acid (GDCA) at doses ranging from 0.1 to 1.0 mmol/L had no cytotoxic effects on AR42J cells. Deoxycholic acid (DCA), chenodeoxycholic acid (CDCA) and lithocholic acid (LCA) at doses ≥ 0.3 mmol/L, and taurodeoxycholic acid (TDCA) at doses ≥ 0.4 mmol/L induced cytotoxic effects on AR42J cells in a dose-dependent manner. No significant differences were noted in the apoptotic rate and necrotic rate between untreated AR42J cells and those treated with 0.8 mmol/L of CA (apoptotic rate: 1.2% vs 0.9%; necrotic rate: 1.0% vs 1.0%). The apoptotic rate and necrotic rate of AR42J cells treated with 0.4 mmol/L of DCA were 45.2% and 8.9%, respectively, while those treated with 0.8 mmol/L of DCA were 18.6% and 45.4%, respectively.

CONCLUSION: Different bile acids exert different cytotoxic effects on AR42J cells. Some bile acids induce the apoptosis and/or necrosis of AR42J cells in a dose-dependent manner.