Background: Type 2 Diabetes (T2D) is a metabolic disease which affects glucose homeostasis
caused due to inability of the target cells to respond to insulin. Role of vitamin D in the
pathogenesis and prevention of T2D has sparked widespread interest. Vitamin D plays a classical
role in Ca++ homeostasis as well as regulates insulin secretion from β-cells and its action on various
target cells. Proteins are the vital components of all cellular processes and their expression alters in
response to various external or internal stimuli. Alteration in protein structure, function may contribute
to the pathogenesis of many diseases including diabetes. Protein expression during the exposure
of the cells to different glucose concentrations may alter and can give vital information about
the pathogenesis of T2D.
Objective: To study the effect of different glucose concentrations and supplementation of vitamin D
on proteomic profile of L6 cell lines.
Method: L6 skeletal muscle cells were exposed to different Glucose (G) concentrations (0mM,
8mM, 16mM and 25mM) supplemented with Vitamin D (VD) for 48 hours. Total cell protein was
extracted and protein profile was studied using SDS-PAGE. Three distinct bands observed in SDSPAGE
in samples obtained from cells which were exposed to 8mM (G), 8mM (G) + VD and 16mM
(G). The distinct bands were excised, in gel digestion were performed and MALDI-TOF analysis of
the samples were done.
Results: MALDI-TOF analysis revealed these bands as mitochondrial uncoupling protein 3 (UCP3
MOUSE), Insulin gene enhancer protein 2 (ISL2 MOUSE) and Tubulin polyglutamylase complex1
(TPGS1 MOUSE) respectively. UCP3 protein is primarily expressed in the skeletal muscle cells
and is involved in energy homeostasis and modulates insulin sensitivity. ISL2 protein plays an important
role in differentiation and maintenance of the tissues. TPGS1 helps in microtubule polymerization
might be helping in glucose transport and also play crucial role in the cellular movement,
organization of intracellular structure, and intracellular transport.
Conclusion: These identified proteins may provide information about disease pathophysiology and
can serve as potential targets for therapeutic intervention of T2D. Further studies on the changes of
protein expression under high glucose concentration and supplementation with vitamin D will lead
to better understanding of the molecular mechanisms of T2D.