Reduced levels of insulin-like growth factor-1 receptor (IGF-1R) suppress cellular signaling in experimental autoimmune sialadenitis (EAS)

+3179G/A Insulin-Like Growth Factor-1 Receptor Polymorphism: A Novel Susceptibility Contributor in Anti-Ro/SSA Positive Patients with Sjögren's Syndrome: Potential Clinical and Pathogenetic Implications

Background: Alterations of the insulin-like growth factor (IGF) pathway along with genetic variations of the IGF1 receptor (IGF1R) gene have been linked to the development of systemic autoimmunity, possibly through apoptosis induction. This study aims to investigate whether genetic variations of the IGF1R contribute to Sjögren’s syndrome (SS) pathogenesis and explores potential functional implications. Methods: DNA extracted from whole peripheral blood derived from 277 primary SS patients, complicated or not by lymphoma, and 337 Healthy controls (HC) was genotyped for the rs2229765 IGF1R polymorphism using the RFLP-PCR assay. Gene expression of IGF1R and IGF1 isoforms, caspases 1, 4, and 5, and inflammasome components NLRP3, ASC, IL1β, IL18, IL33, IGFBP3, and IGFBP6 were quantitated by RT-PCR in total RNA extracted from minor salivary gland biopsies (MSGs) of 50 SS patients and 13 sicca controls (SCs). In addition, IGF1R immunohistochemical (IHC) expression was assessed in formalin-fixed, paraffin-embedded MSG tissue sections derived from 10 SS patients and 5 SCs. Results: The prevalence of the A/A genotype of the rs2229765 IGF1R polymorphism was significantly higher in the anti-Ro/SSA positive SS population compared to healthy controls (24.8% vs. 10.7%, p = 0.001). Moreover, IGF1Rs at both mRNA and protein levels were reduced in SS-derived MSGs compared to SCs and were negatively associated with caspase 1 transcripts. The latter were positively correlated with NLRP3, ASC, and IL1β at the salivary gland tissue level. IGF1R expression in peripheral blood was negatively correlated with ESR and IgG serum levels and positively correlated with urine-specific gravity values. Conclusions: The rs2229765 IGF1R variant confers increased susceptibility for seropositive primary SS. Dampened IGF1R mRNA and protein expression in salivary gland tissues could be related to increased apoptosis and subsequently to the activation of inflammasome pathways.

The Emerging Role of the Insulin-like Growth Factors in Oral Biology

The insulin-like growth factors (IGF) are a family of growth factors, receptors and binding proteins that are involved in numerous growth and differentiation processes, as well as in various pathological conditions. The aim of this review is to summarize data that has been accumulating in recent years linking the IGF system to a number of physiological and pathological oral processes. The IGF system fulfills an important role in growth and development of teeth, mandible, maxillae, and tongue. It has been postulated that IGF-I may be of great value in the treatment of periodontal defects and in tissue healing. Furthermore, IGF-II has been shown to be overexpressed in salivary gland adenomas, suggesting that aberrant IGF signaling may be a key factor in the etiology of oral malignancies. Understanding the role and regulation of IGF system components in salivary glands and other oral structures will be of significant basic and clinical relevance.

IGF-I and INS receptor expression in the salivary glands of diabetic Nod mice submitted to long-term insulin treatment

This work aimed to characterize the IGF-I and INS receptor expression in the salivary glands of Nod mice, correlating to therapeutic effects of insulin treatment on these receptors. Nod mice were divided into: Groups 1 and 2 (diabetic), Groups 3 and 4 (diabetic with insulin treatment) and Group 5 (non-diabetic). Fragments from the salivary glands were processed for immunohistochemical analysis. The results showed that the prolonged diabetic state led to a steadily increased IGF-I receptor expression. INS receptor expression was gradually decreased. It was concluded that not only was the IGF-I receptor expression affected by the diabetic state but also the INS receptor expression. The period of the diabetic state was directly related to changes in the expression of these receptors. In spite of the insulin treatment having recovered the glycaemic levels, the expression of INS and the IGF-I receptors did not reach the standard level, which certainly hampered glandular function.

Peripheral blood gene expression profiling in Sjögren's syndrome

Sjögren’s syndrome (SS) is a common chronic autoimmune disease characterized by lymphocytic infiltration of exocrine glands. Affected cases commonly present with oral and ocular dryness, thought to be the result of inflammatory cell-mediated gland dysfunction. To identify important molecular pathways involved in SS, we used high-density microarrays to define global gene expression profiles in peripheral blood. We first analyzed 21 SS cases and 23 controls and identified a prominent pattern of overexpressed genes that are inducible by interferons (IFNs). These results were confirmed by evaluation of a second independent dataset of 17 SS cases and 22 controls. Additional inflammatory and immune-related pathways with altered expression patterns in SS cases included B and T cell receptor, IGF-1, GM-CSF, PPARα/RXRα, and PI3/AKT signaling. Exploration of these data for relationships to clinical features of disease revealed that expression levels for most IFN-inducible genes were positively correlated with titers of anti-Ro/SSA (P<0.001) and anti-La/SSB (P<0.001) autoantibodies. Diagnostic and therapeutic approaches targeting IFN signaling pathway may prove most effective in the subset of SS cases who produce anti-Ro/SSA and anti-La/SSB autoantibodies. Our results strongly support innate and adaptive immune processes in the pathogenesis of SS and provide numerous candidate disease markers for further study.

Expression patterns and action analysis of genes associated with physiological responses during rat liver regeneration: cellular immune response

AIM

To study the cellular immune response during rat liver regeneration (LR) at a transcriptional level.

METHODS

Genes associated with the cellular immune response were obtained by collecting the data from databases and retrieving articles. Gene expression changes during LR were detected by rat genome 230 2.0 array.

RESULTS

A total of 127 genes were found to be associated with LR. The number of initially and totally expressing genes in the initial phase of LR [0.5-4 h after partial hepatectomy (PH)], transition from G(0)-G(1) (4-6 h after PH), cell proliferation (6-66 h after PH), cell differentiation and structure-function reconstruction (66-168 h after PH) was 54, 11, 34, 3 and 54, 49, 70, 49 respectively, illustrating that the associated genes were mainly triggered at the initiation of LR, and worked at different phases. According to their expression similarity, these genes were classified into 41 up-regulated, 21 predominantly up-regulated, 41 down-regulated, 14 predominantly down-regulated, 10 similarly up-regulated and down-regulated genes, respectively. The total up- and down-regulated expression times were 419 and 274, respectively, demonstrating that the expression of most genes was increased while the expression of a small number of genes was decreased. Their time relevance was classified into 14 groups, showing that the cellular physiological and biochemical activities were staggered during LR. According to the gene expression patterns, they were classified into 21 types, showing the activities were diverse and complicated during LR.

CONCLUSION

Antigen processing and presentation are enhanced mainly in the forepart, prophase and anaphase of LR. T-cell activation and antigen elimination are enhanced mainly in the forepart and prophase of LR. A total of 127 genes associated with LR play an important role in cellular immunity.

IGF-1 and insulin receptor expression in the minor salivary gland tissues of Sjögren's syndrome and mucoceles--immunohistochemical study

OBJECTIVE

To investigate the expression of IGF-1 receptors and insulin receptors on the minor salivary gland (MSG) tissues of patients diagnosed with Sjögren's syndrome (SS) and normal salivary gland tissue surrounding mucoceles.

SUBJECTS AND METHODS

Five MSG tissue sections from SS and seven from mucocele patients were stained immunohistochemically using antibody to IGF-1 receptor and insulin receptor in a horse radish peroxidase and DAB system.

RESULTS

The expression of the insulin receptor was increased in the SS sections compared with controls, while the insulin-like growth factor-1 receptor was more intensely expressed in the controls.

CONCLUSION

The presence of differential expression of receptors for IGF and insulin might suggest a possible role of these growth factors in the pathogenesis of SS.