ABSTRACT TITLE

Novel Molecular Target and Therapeutics for Autoimmune Diabetes.

PRESENTING AUTHOR WITH QUALIFICATIONS AND AFFILIATIONS:

Parameswaran Ramakrishnan, M.Sc, Ph.D. Case Western Reserve University and University Hospitals Cleveland Medical Center, Cleveland, OH, USA Cleveland Clinic Foundation, Cleveland, OH, USA Case Comprehensive Cancer Center.

LIST OF AUTHORS WITH THEIR WITH QUALIFICATIONS AND AFFILIATIONS:

Jon Pokorski, Ph.D, University of California San Diego, La Jolla, CA, USA Joshua Centore, Case Western Reserve University, Cleveland, OH, USA Derek Church, Ph.D, University of California San Diego, La Jolla, CA, USA Tristan De Jesus, Case Western Reserve University, Cleveland, OH, USA.

ABSTRACT:

Background

Type 1 diabetes is an autoimmune disease associated with hyperglycemia. Adverse pathological effects of hyperglycemia include enhanced hexosamine biosynthetic pathway and intracellular posttranslational modification of proteins by the sugar N-acetyl glucosamine (GlcNAc) in a process called O-GlcNAcylation. We discovered that hyperglycemia increases the O-GlcNAcylation of the transcription factor, nuclear factor kappaB (NF-kB) c-Rel at serine 350. O-GlcNAcylation of c-Rel activates transcription of proautoimmune cytokines, interleukin 2 (IL-2), interferon gamma (IFNG)and granulocyte macrophage-colony stimulating factor (GM-CSF)and inhibits the expression of T-regulatory cell specific transcription factor FOXP3in T cells. These reciprocal effects caused by c-Rel O-GlcNAcylation may act as positive feedback accelerator of autoimmunity under hyperglycemia. Hence, blocking O-GlcNAcylated c-Rel function will have dual benefits in controlling autoimmune diabetes by diminishing the T cell-mediated autoimmunity and enhancing the T-regulatory cell function to suppress autoimmunity.

Aim

To develop agents with therapeutic potential to block the function of O-GlcNAcylated c-Rel to treat autoimmunity in diabetes.

Methods

We modeled a modified coarse grained, energy-minimized model of the S350 O-GlcNAcylated c-Rel peptide. We iteratively designed peptoids, a class of peptidomimetics, in silicoand input into molecular docking software and identified peptoid3 with highest affinity for binding to the S350 O-GlcNAcylated c-Rel peptide. We synthesized peptoid3 and scrambled control peptoid using standard sub-monomer synthetic procedures with Rink-Amide resin followed by trifluoroacetic acid cleavage. Peptoids were purified to greater than 90% purity using reverse-phase HPLC and analyzed by mass spectrometry. We examined the effect of peptoid3 treatment on T cell receptor-induced binding of O-GlcNAcylated c-Rel to DNA and autoimmune gene expression in CD4+T cells.

Results and Conclusions

We found that peptoid3 treatment significantly decreased T cell receptor-induced, O-GlcNAcylation-dependent expression of proautoimmune cytokines and enhanced FOXP3 expression in T cells. Peptoid3 treatment selectively affected autoimmunity-associated genes and did not exhibit toxicity on survival or proliferation of T cells. Broad inhibition of hexosamine biosynthetic pathway or NF-kB will cause many side effects due to their ubiquitous importance in multiple biological functions. Therefore, inhibitors of O-GlcNAcylated NF-kB c-Rel function may prove long-sought-after specific molecular therapeutic, with minimal side effects, to diminish autoimmunity in type 1 diabetes.

PREVALENCE OF INSULIN RESISTANCE IN NON-OBESE, EUGLYCEMIC AND NORMOTENSIVE FIRST DEGREE RELATIVES OF OBESE INDIVIDUALS.

Nishanth Dev1, Jhuma Sankar2

1. Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India

2. All India Institute of Medical Sciences, New Delhi, India

Background & Aim

Insulin resistance (IR) is an important etiology for development of prediabetes and type-2 diabetes. While most studies have focused on the prevalence of IR in obese, diabetics and hypertensive individuals, there is scarcity of literature on the first-degree relatives of these populations. The study was undertaken to estimate the prevalence of IR in Normotensive, euglycemic, non-obese first- degree relatives of obese individuals.

Material & Methods

This cross-sectional study included 35 first degree non-obese, euglycemic and normotensive relatives of obese individuals compared with 35 matched first degree relatives of non-obese individuals. The enrolled individuals were subjected to history, clinical examination and investigations. Insulin resistance was defined as Homeostasis model assessment-estimated insulin resistance (HOMA IR)value exceeding the 75th percentile of the total study group.

Results

The prevalence (95% CI) of insulin resistance was 34% (21 to 51) in the study group as compared to 14% (6 to 9%) in the comparison group (p=0.05), (Odds ratio (OR) 95% CI: 2.4 (0.94 to 6.09). The corresponding mean HOMA IR levels were 2.5 and 2.2 respectively. Impaired fasting glucose levels were seen in 26% in study group as compared to 11% in the comparison group (OR: 2.25 (0.76 to 6.62)). Higher proportions of subjects in the study group had impaired glucose tolerance compared to the comparison group (23% vs. 9%; OR: 2.67 (0.77 to 9.23)). The mean fasting as well as post-prandial glucose levels were higher in those with IR as compared to those without (98 vs. 88, p=0.002 and 128 vs. 121, p=0.05 respectively). All individuals with IR had increased serum insulin levels and the corresponding meanserum insulin levels were 184 as compared to 114 in those without IR (p <0.0001). The differences in lipid parameters were not statistically significant between the groups.

Conclusion

The study demonstrates significant burden of Insulin resistance in healthy relatives of obese individuals and should be closely followed up and monitored so that early interventions by means of life style and diet modifications can be done. Our findings are hypothesis generating and exploratory which needs further confirmation by larger studies.

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