New DiaP277 analogue shifts DCs to tolerogenic, and modulates NF-Kβ1 to suppress autoreactive T lymphocytes in the type 1 diabetic mice

Abstract

Therapeutic efficacy of P277 against type 1 diabetes was extensively investigated and clinically evidenced. Clinical trials Phases I and II concluded promising results, while the data of P277 immunogenicity in Phase III trials represented weak responses that led to abolish medical use. But, a therapeutic performance of P277 cannot be forgotten. So, in order to exploit its therapeutic benefits and improve its immunogenicity, we developed a new analogue VP to optimize therapeutic efficacy and enhancing immunosuppressive modulations. However, new analogue was purified, and then used to immunize diabetic NOD mice to investigate antidiabetic effects through modulation of immunological status. So, DCs immune responses, relative TLRs, MyD88, and NF-Kβ1 mRNA expression on DCs and splenocytes under VP effect were tested. Circulating and intracellular cytokines were also evaluated at treated and non-treated mice. Splenic T lymphocytes proliferation (Th1 and Treg cells) were also determined. Results revealed that VP significantly down regulates DCs maturation through TLR2, TLR4, and MyD88 pathways. It also shifts DCs to a tolerogenic polarization through NF-Kβ1 pathway that mediates Th1 immunosuppression and enhances iTreg expanding in type1diabetes mice. Meanwhile, we noticed that VP significantly enhances iTreg CD25 + FoxP3+ proliferation. In conclusion, VP showed promising immune potential to modulate immune regulatory responses and shifts DCs to suppress autoreactive Th1 cells which ameliorated immunosuppressive potency in the type1 diabetic mice.

Keywords:

• VP peptide
• P277
• tolerogenic DCs
• TLRs
• NF-Kβ1

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was funded by National High Technology Research and Development Program of China (863 Program, No. 2015AA020314); Supported by National Natural Science Foundation of China (Grant nos. 81570696 and 31270985); Supported by Excellent Youth Foundation of Jiangsu Scientific Committee (BK20140029); Supported by sponsored by Qing Lan Project; Supported by Program for Jiangsu Province Innovative Research Team; Supported by grants from the ‘111’ project (B16046) from the Ministry of Education of China of the State Administration of Foreign Experts Affairs of China; Priority Academic Program Development of Jiangsu Higher Education Institutions, the Project Program of State Key Laboratory of Natural Medicines, China Pharmaceutical University (No. SKLNMZZCX201601); the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD); and National training programs of Innovation and Entrepreneurship for undergraduates (J1310032).