Immunization with P277 induces vascular leak syndrome in C57BL/6 mice via endothelial damage

Continuous stimulation of dual-function peptide PGLP-1-VP inhibits the morbidity and mortality of NOD mice through anti-inflammation and immunoregulation

Multiple animal and human studies have shown that administration of GLP-1RA can enhance β-cell recovery, reduce insulin dosage, reduce HbA1c content in the blood, reduce the risk of hypoglycemia and reduce inflammation. In the NOD mouse model, peptide VP treatment can prevent and treat type 1 diabetes through immunomodulation. Therefore, we designed a new dual-functional PGLP-1-VP, which is expected to combine the anti-inflammatory effect of PGLP-1 and the immunomodulatory effect of VP peptide. In streptozotocin-induced hyperglycemic mice model, we demonstrated that PGLP-1-VP can act as a GLP-1R agonist to improve hyperglycemia and increase insulin sensitivity. In the NOD mouse model, PGLP-1-VP treatment reduced morbidity, mortality, and pancreatic inflammation, and showed superior effect to PGLP-1 or VP treatment alone, confirming that PGLP-1-VP may act as a dual-function peptide. PGLP-1-VP provided immunomodulatory effect through increasing Th2 cell percentage and balancing the ratio of Th2/Th1 in spleen and PLN, similar to P277 and VP. Additionally, PGLP-1-VP and PGLP-1 act the anti-inflammation by increasing Treg cells and TGF-β1 content like DPP-IV inhibitor. Taken together, our data shows that the dual-functional PGLP-1-VP reduces morbidity and mortality in the NOD model, suggesting a potential role in preventing and treating type 1 diabetes.

Peptidic vaccines: The new cure for heart diseases?

Cardiovascular disease continues to be the most common cause of death worldwide. The global burden is so high that numerous organizations are providing counseling recommendations and annual revisions of current pharmacological and non-pharmacological treatments as well as risk prediction for disease prevention and further progression. Although primary preventive interventions targeting risk factors such as obesity, hypertension, smoking, and sedentarism have led to a global decline in hospitalization rates, the aging population has overwhelmed these efforts on a global scale. This review focuses on peptidic vaccines, with the known and not well-known autoantigens in atheroma formation or acquired cardiac diseases, as novel potential immunotherapy approaches to counteract harmful heart disease continuance. We summarize how cancer immunomodulatory strategies started novel approaches to modulate the innate and adaptive immune responses, and how they can be targeted for therapeutic purposes in the cardiovascular system. Brief descriptions focused on the processes that start as either immunologic or non-immunologic, and the ultimate loss of cardiac muscle cell contractility as the outcome, are discussed. We conclude debating how novel strategies with nanoparticles and nanovaccines open a promising therapeutic option to reduce or prevent cardiovascular diseases.

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

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.

Novel mutant P277 peptide VP to ameliorate atherogenic side-effects and to preserve anti-diabetic effects in NOD mice

P277 is a 24 amino-acids peptide, residues 437-460 of human heat shock protein 60 (HSP60). P277 or sequence repeated 6 × P277 was previously found showing potency preventive and therapeutic anti-diabetes functions in NOD mice, but aroused atherosclerosis due to the induction of anti-HSP65 autoantibodies as reported. To determine the intrinsic B epitope sequence, we screened P277 with pepscan method and then proved by detection of sera IgG from peptide fragments vaccinated mouse and rabbits. Results indicated HSP60 443-448 (ALLRCI) is potential intrinsic B epitope sequence of P277. We modified P277 by deleting the former three amino acids of ALLRCI (VP) or replacing these six with alanine (AP). The detection of serum lipid parameter in NOD mice and aorta endothelial damage levels in high-cholesterol diets fed rabbits demonstrated that VP induced higher anti-diabetes efficacy and caused less arteriosclerosis-liked diseases separately. With less TLR2/4 activation of dendritic cells and macrophages, VP treatment reduced Th1 related P277 specific pro-inflammatory cytokines production and increased regulatory immune responses both in vivo and in vitro. These results indicated that optimized VP peptide might serve as a promising candidate for mouse type 1 diabetes therapy.

A rationally designed peptide IA-2-P2 against type 1 diabetes in streptozotocin-induced diabetic mice

Recent studies have investigated the potential of type 1 diabetes mellitus-related autoantigens, such as heat shock protein 60, to induce immunological tolerance or to suppress the immune response. A functional 24-residue peptide derived from heat shock protein 60 (P277) has shown anti-type 1 diabetes mellitus potential in experimental animals and in clinical studies, but it also carries a potential atherogenic effect. In this study, we have modified P277 to retain an anti-type 1 diabetes mellitus effect and minimize the atherogenic potential by replacing the P277 B epitope with another diabetes-associated autoantigen, insulinoma antigen-2 (IA-2), to create the fusion peptide IA-2-P2. In streptozotocin-induced diabetic C57BL/6J mice, the IA-2-P2 peptide displayed similar anti-diabetic effects to the control P277 peptide. Also, the IA-2-P2 peptide did not show atherogenic activity in a rabbit model. Our findings indicate the potential of IA-2-P2 as a promising vaccine against type 1 diabetes mellitus.

Promotion of atherosclerosis in high cholesterol diet-fed rabbits by immunization with the P277 peptide

Previous evidence has proved the ability of immunization with heat shock protein (HSP) 60/65 to induce atherosclerosis. P277, a 24-residue peptide of human HSP60, is a promising peptide vaccine against autoimmune diabetes. But as a fragment of HSP60, its potential ability of promoting atherosclerosis has never been investigated yet. In the present study, the rabbits fed with normal standard diet or high cholesterol diet were immunized with P277 or PBS emulsified in incomplete Freund's adjuvant 4 times at 4-week intervals. Atherosclerotic lesions of the rabbits receiving P277 treatment and fed with high cholesterol diet increased significantly compared with those of the rabbits receiving PBS treatment and the same diet. However, no obvious lesions were found in the two groups of rabbits fed with the normal standard diet. Significant expression of P277 was detected in the high cholesterol diet-induced atherosclerotic lesions and heat-stressed endothelial cells. Surface exposure of P277 was also observed in the stressed cells. In the subsequent assay of endothelial cells in vitro, the purified anti-P277 antibodies mediated a noticeable cytotoxicity to the stressed cells with the participation of complement. In conclusion, subcutaneous immunization with P277 emulsified in IFA can aggravate the atherosclerosis in high cholesterol diet-fed rabbits. Surface expression of P277 was observed on stressed endothelial cells, and were suggested to mediate the autoimmune attack and promote the disease.

Epitopes of microbial and human heat shock protein 60 and their recognition in myalgic encephalomyelitis

Myalgic encephalomyelitis (ME, also called Chronic Fatigue Syndrome), a common disease with chronic fatigability, cognitive dysfunction and myalgia of unknown etiology, often starts with an infection. The chaperonin human heat shock protein 60 (HSP60) occurs in mitochondria and in bacteria, is highly conserved, antigenic and a major autoantigen. The anti-HSP60 humoral (IgG and IgM) immune response was studied in 69 ME patients and 76 blood donors (BD) (the Training set) with recombinant human and E coli HSP60, and 136 30-mer overlapping and targeted peptides from HSP60 of humans, Chlamydia, Mycoplasma and 26 other species in a multiplex suspension array. Peptides from HSP60 helix I had a chaperonin-like activity, but these and other HSP60 peptides also bound IgG and IgM with an ME preference, theoretically indicating a competition between HSP60 function and antibody binding. A HSP60-based panel of 25 antigens was selected. When evaluated with 61 other ME and 399 non-ME samples (331 BD, 20 Multiple Sclerosis and 48 Systemic Lupus Erythematosus patients), a peptide from Chlamydia pneumoniae HSP60 detected IgM in 15 of 61 (24%) of ME, and in 1 of 399 non-ME at a high cutoff (p<0.0001). IgM to specific cross-reactive epitopes of human and microbial HSP60 occurs in a subset of ME, compatible with infection-induced autoimmunity.