Effects of Type 2 Diabetes Mellitus on Gene Expressions of Mouse Meibomian Glands

ABSTRACT

Purpose

Type 2 Diabetes mellitus (DM) is a major health problem and its ocular complications like orbital infections, cataract and diabetic retinopathy cause blindness. Meibomian gland (MG) dysfunction and dry eye disease are also important ocular complications of type 2 DM but not enough research has been conducted on these complications. Our hypothesis suggests type 2 DM can alter significant gene expressions of MG. In our study, MGs of leptin-deficient spontaneous diabetic and non-diabetic mice were extracted, and gene expression profiles were analyzed with microarray technology.

Methods

Mice were divided into two groups; nine Lep ^b/ob spontaneous diabetic mice as type 2 DM group and nine non-diabetic Balb/c mice as controls. Blood glucose levels, tearfilm break-up time and fluorescein scores were measured in both two groups for 12 weeks. MGs were dissected and RNAs were isolated for microarray gene expression analysis. We filtered probes with standard deviation of more than 0.1 and we used 40452 of 45281 probes for processing. We performed fold change analysis and identified which genes are affected, and we analyzed the impact of genes on proteins, pathways and gene ontologies by using various databases.

Results

We observed 172 up-regulated and 118 down-regulated genes in type 2 diabetic mice when compared to non-diabetic mice. Interestingly, expression of collagen type I, integrin beta-I binding protein-I, pyruvate dehydrogenase kinase, TNF receptor genes up-regulated with DM; on the other hand, IL-33, cholecystokinin, plasminogen activator, IL-1 and serine peptidase inhibitor genes down-regulated significantly. Also, we have seen a significant decrease in WNT signaling and pentose phosphate pathways-related genes.

Conclusion

Our data show these changes in gene expression caused by endocrine and immune mechanisms of type 2 DM which result disrupted homeostasis of epithelial cells of MG. Increased expressions of apoptosis and inflammation-related genes and their effects on related pathways have proven that MGs were negatively affected by type-2 DM.

KEYWORDS:

• Meibomian glands
• Type 2 diabetes mellitus
• Meibomian gland dysfunction
• dry eye disease
• inflammation
• Apoptosis
• gene expression
• microarray analysis

Acknowledgments

The authors thank Hacettepe University and Koç University Research Center for Translational Medicine (KUTTAM), funded by the Republic of Turkey Ministry of Development, for allowing us to use their services and facilities. The content of the manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the Ministry of Development.

Declaration of Interest

The authors report no conflicts of interest.

Additional information

Funding

This research project funded by Scientific and Technological Research Council of Turkey (Türkiye Bilimsel ve Teknolojik Araştırma Kurumu) under ARDEB 1002 grant program with 115S069 project number. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Scientific and Technological Research Council of Turkey.