CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/KR2018/004803 filed Apr. 25, 2018, claiming priority based on Korean Patent Application No. 10-2017-0056842 filed May 4, 2017 and Korean Patent Application No. 10-2018-0046715 filed Apr. 23, 2018.

SEQUENCE LISTING

The content of the electronically submitted sequence listing, file name: Sequence_Listing_As_Filed_20211214.txt; size: 16,533 bytes; and date of creation: Dec. 13, 2021, filed herewith, is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a fusion peptide that inhibits signaling pathways of Toll-like receptor (TLR)1/2, TLR2/6, TLR7, TLR8, and TLR9 as well as TLR4 and TLR3, and a pharmaceutical composition for preventing or treating a TLR pathway-mediated disease, comprising the same.

BACKGROUND ART

Innate immunity is the first line of defense against bacterial infection in a mammalian immune system and is activated via recognition of pathogen-associated molecular patterns (PAMPs) or danger-associated molecular patterns (DAMPs) by pattern recognition receptors such as Toll-like receptors (TLRs).

TLRs play an important role in innate immune responses and may be divided into extracellular TLRs, which act on the plasma membrane and include TLR1, TLR2, TLR4, TLR5, TLR6, and TLR11, and intracellular TLRs, which act in the inside of cell such as endosome and include TLR3, TLR7, TLR8, and TLR9. Structurally, TLRs have a leucine-rich repeat (LRR) site, which is recognized by a ligand or an accessory molecule, at the N-terminus of the extracellular domain, and a Toll/interleukin 1 receptor (TIR) domain, which transduces a signal, at the C-terminus of the intracellular portion.

In particular, TLR4 is the first identified receptor in the TLR family, and activates innate immune signals which are amplified through myeloid differentiation 88 (MyD88)-dependent and MyD88-independent signaling pathways. In contrast, TLR3 activates only the MyD88-independent signaling pathway. Due to this role of TLRs, there is a growing interest in studies intended to use TLRs as targets for treating various immune diseases.

MyD88-dependent signaling of TLR4 is initiated by LPS recognition through accessory molecules such as cluster of differentiation 14 (CD14) and myeloid differentiation factor 2 (MD2). After binding of LPS, TLR4 dimerizes, which allows the TIR domain of TLR4 and the TIR domain of TIR domain adapter protein (TIRAP or MyD88 adapter-like (MAL)) to bind to each other so as to form a complex with MyD88, thereby activating its signaling pathway. Activated TLR4 induces early activation of NFκB, migration to the nucleus, and activation of MAPK, through a Myd88-dependent signaling process. The activation of NFκB and MAPK secretes inflammatory cytokines such as tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6). MyD88-independent signaling processes of TLR4 and TLR3 are initiated by binding between TIR domain of each TLR and TIR domain of TIR domain-containing adapter-inducing interferon-β (TRIF)/TRIF-related adaptor molecule (TRAM) complex, and secrete type 1 interferons by activation of interferon-regulatory factors (IRFs). In addition, TLR4 activity produces oxidative stressors such as NO and ROS in macrophages.

As such, since TLRs may be targets for treating various diseases such as autoimmune diseases, inflammatory diseases, and cancer, studies on substances targeting TLRs and medical compositions for treating diseases related to TLRs have been conducted. In particular, a number of TLR4 promoters and antagonists have been obtained by modifying the main skeletal structure of lipid A, and it has been found that eritoran, lipid A, andRhodobacter sphaeroidslipid A (RsLA) can inhibit interaction between LPS and MD2 and prevent LPS-induced shock in mice. In addition, it has been reported that the TLR4 signaling pathway induced by LPS is involved in formation of NLRP3 inflammasome, and thus is closely related to degenerative neurological diseases such as Alzheimer's disease and Parkinson's disease.

On the other hand, studies are actively conducted on peptides that act similar to or opposite to pathogen-associated molecular patterns (PAMPs) by using decoy peptides which use a part of a binding domain of a protein and control signaling by binding, in place of the protein, to a protein that originally interacts therewith. Peptides are known to have fewer side effects, and easier modification and quality control, than common small-molecule therapeutic agents, and low cell permeability thereof is also improved due to development of cell-penetrating peptides (CPPs).

DISCLOSURE OF INVENTION

Technical Problem

The present inventors have identified that a novel peptide (decoy peptide 1) consisting of the amino acid sequence of SEQ ID NO: 1, and a fusion peptide (Toll-like receptor inhibitory peptide 1, TIP1) in which the novel peptide is linked to the N-terminus of a cell-penetrating peptide inhibit a lipopolysaccharide (LPS)-induced TLR4 signaling pathway, thereby not only inhibiting secretion of cytokines (IL-6, TNF-α, IFN-β), NO, and ROS, and activation of NF-κB and MAPK, but also alleviating renal and hepatic damage caused by hyperactivity of TLR4, sepsis, and rheumatoid arthritis in animals. The present inventors have also proven that the novel peptide and the fusion peptide inhibit a TLR3 signaling pathway induced by Poly(I:C) and formation of NLRP3 inflammasome induced by LPS/ATP, thereby completing the present invention. In addition, it was identified by cell experiments that the novel peptide and the fusion peptide also partially inhibit TLR1/2, TLR2/6, TLR7, TLR8, and TLR9.

Accordingly, an object of the present invention is to provide a peptide consisting of the amino acid sequence of SEQ ID NO: 1, and a fusion peptide in which a peptide consisting of the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2 is linked to the N-terminus of a cell-penetrating peptide.

In addition, another object of the present invention is to provide a pharmaceutical composition for preventing or treating at least one TLR pathway-mediated disease selected from the group consisting of autoimmune diseases, inflammatory diseases, and degenerative neurological diseases, comprising, as an active ingredient, a peptide consisting of the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2.

Solution to Problem

In order to achieve the above objects, the present invention provides a peptide consisting of the amino acid sequence of SEQ ID NO: 1.

In addition, the present invention provides a fusion peptide in which a peptide consisting of the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2 is linked to the N-terminus of a cell-penetrating peptide.

In addition, the present invention provides a pharmaceutical composition for preventing or treating at least one TLR pathway-mediated disease selected from the group consisting of autoimmune diseases, inflammatory diseases, and degenerative neurological diseases, comprising, as an active ingredient, a peptide consisting of the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2.

In addition, the present invention provides a pharmaceutical composition for preventing or treating at least one TLR pathway-mediated disease selected from the group consisting of autoimmune diseases, inflammatory diseases, and degenerative neurological diseases, comprising, as an active ingredient, a fusion peptide in which a peptide consisting of the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2 is linked to the N-terminus of a cell-penetrating peptide.

Advantageous Effects of Invention

The fusion peptide of the present invention has an excellent effect of inhibiting signaling pathways of various TLRs including TLR4, and thus hinders immune responses mediated by the TLRs so that the fusion peptide can be usefully used for preventing and treating various TLR pathway-mediated diseases caused by the signaling pathways, such as autoimmune diseases, inflammatory diseases, or degenerative neurological diseases.

