N-terminally truncated interleukin-38

Abstract

The present invention pertains to an N-terminally truncated interleukin (IL)-38 protein, or functional variants thereof, as well as to nucleic acids and vectors encoding the truncated IL-38 peptide and recombinant cells comprising these nucleic acids or vectors. The invention shows that IL-38 is N-terminally processed and that the truncated version of the cytokine acts as an antagonist of immune activation in macrophages. This indicates a use of the truncated cytokine in the treatment and prevention of autoimmune disorders. The invention further provides pharmaceutical compositions comprising the truncated IL-38 protein, and method for screening modulators of the function of truncated IL-38.

1 . An isolated truncated IL-38 protein, or a functional variant thereof, wherein said truncated IL-38 protein is N-terminally truncated compared to the amino acid sequence according to SEQ ID NO: 1, and wherein said truncation comprises at least 10 adjoining amino acids between positions 1 to 30 of SEQ ID NO: 1. 
     
     
         2 . The isolated truncated IL-38 protein according to  claim 1 , wherein said truncated IL-38 protein has 2-50 amino acids truncated at its N-terminus as compared with wild type IL-38 protein (SEQ ID NO: 1). 
     
     
         3 . The isolated truncated IL38 protein according to  claim 2 , wherein said truncated IL-38 protein has 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 amino acids truncated at its N-terminus as compared to the protein shown in SEQ ID NO: 1. 
     
     
         4 . The truncated IL-38 protein according to  claim 1 , having an N-terminus that is not identical to the first 100, 50, 30, 20, or 19 amino acids of SEQ ID NO: 1. 
     
     
         5 . A nucleic acid comprising a sequence coding for a truncated IL-38 protein according to  claim 1 . 
     
     
         6 . The nucleic acid according to  claim 5  comprising a sequence that when expressed produces a polypeptide consisting of the truncated IL-38 protein and not a full length IL-38 protein according to SEQ ID NO: 1, wherein said truncated IL-38 protein is N-terminally truncated compared to the amino acid sequence according to SEQ ID NO: 1, and wherein said truncation comprises at least 10 adjoining amino acids between positions 1 to 30 of SEQ ID NO: 1. 
     
     
         7 . A vector comprising a nucleic acid according to  claim 5 . 
     
     
         8 . The vector according to  claim 7 , wherein the expressible sequence is operable linked to a promoter. 
     
     
         9 . A recombinant cell, comprising a nucleic acid according to  claim 5 , or a vector comprising said nucleic acid. 
     
     
         10 . A pharmaceutical composition comprising the truncated IL-38 protein according to  claim 1 , or a nucleic acid encoding the truncated IL-38 protein, or a vector comprising the nucleic acid, or a recombinant cell comprising the truncated IL-38 protein, the nucleic acid or the vector. 
     
     
         11 . An in-vitro method for modulating the immune response of a cell, the method comprising contacting said cell with a truncated IL-38 protein according to  claim 1 , or by expressing in said cell a nucleic acid comprising a sequence encoding said truncated IL-38 protein. 
     
     
         12 . The method according to  claim 11 , wherein modulating the immune response is an inhibition of JNK signaling, in particular the inhibition of IL-6 release and TH17 generation. 
     
     
         13 . A method for screening for modulators of the activity of truncated IL-38, comprising the steps of
 a. Providing a cell,   b. Contacting said cell with microbe-associated molecular pattern (MAMP), pathogen-associated molecular patterns (PAMP) or apoptotic cell supernatants (ACM),   c. Further contacting said cell with a truncated IL-38 protein according to  claim 1  and a candidate modulator,   d. Determining JNK activation in said cell,   
       wherein an increase of JNK activation in said cell compared to a control cell or reference value indicates that the candidate modulator is an antagonist of truncated IL-38, and a decrease of JNK activation compared to a control cell or reference indicates that the candidate modulator is an agonist of truncated IL-38. 
     
     
         14 . The method according to  claim 13 , wherein said cell expresses on the cell surface a receptor of truncated IL-38, for example by ectopically expressing IL-1RAPL1 in said cell. 
     
     
         15 . The method according to  claim 13 , wherein said JNK activation is determined by means of an AP-1 reporter construct. 
     
     
         16 . A method for the treatment or prevention of an immune or inflammatory disease in a subject in need of such treatment, the method comprising a step of administering a therapeutically effective amount of any one or a combination of:
 a. an isolated truncated IL-38 protein, or a functional variant thereof, wherein said truncated IL-38 protein is N-terminally truncated compared to the amino acid sequence according to SEQ ID NO: 1, and wherein said truncation comprises at least 10 adjoining amino acids between positions 1 to 30 of SEQ ID NO: 1; and/or   b. a nucleic acid, or a vector or recombinant cell comprising the nucleic acid, wherein the nucleic acid comprises a sequence coding for a truncated IL-38 protein or a functional variant thereof, wherein said truncated IL-38 protein is N-terminally truncated compared to the amino acid sequence according to SEQ ID NO: 1, and wherein said truncation comprises at least 10 adjoining amino acids between positions 1 to 30 of SEQ ID NO: 1.   
     
     
         17 . The method according to  claim 16 , wherein the immune or inflammatory disease is selected from autoimmune diseases, such as septic shock, hemorrhagic shock, arthritis, for example spondyloarthritis, rheumatoid arthritis, psoriatic arthritis or osteoarthritis, inflammatory bowel disease, multiple sclerosis and meta-bolic diseases such as arteriosclerosis and type I diabetes; or is Muckle-Wells syndrome, cryopyrin-associated periodic fever syndromes (CAPS), familial Mediterranean fever, Still's disease, Behcet's disease or diabetes mellitus.