Tag Archives: glucose deprivation
Glucose deprivation-induced glycogen degradation and viability are altered in peripheral blood mononuclear cells of type 2 diabetes patients
K. S. Praveen Kumar1, P. Kamarthy2, S. Balakrishna1*
1Department of Cell Biology and Molecular Genetics, Sri Devaraj Urs Academy of Higher Education, Kolar, India;
2Department of General Medicine, Sri Devaraj Urs Medical College, Tamaka, Kolar, India;
*e-mail: sharath@sduu.ac.in
Received: 07 September 2021; Accepted: 21 January 2022
The glycogen pathway plays an important role in glucose homeostasis. Impairment of the glycogen pathway has been linked to diabetes mellitus. The aim of the study is to compare the levels of glucose deprivation-induced glycogen degradation and cell viability in peripheral blood mononuclear cells from type 2 diabetes mellitus patients and healthy controls. This was a case-control study comprising 45 T2DM patients and 45 healthy controls. PBMCs were prepared from peripheral blood by density gradient centrifugation. Glycogen levels were measured by the periodic acid-schiff (PAS) staining method. Glycogen degradation was measured as percent change in PAS-stained cells before and after glucose deprivation. PBMC viability was measured by trypan-blue assay. The levels of glucose deprivation-induced glycogen degradation were 55.4% (IQR: 50.6–61.3) in the T2DM group and 70.5% (IQR: 63.9–72.2) in the healthy control group. The difference between the two groups was statistically significant (P = 0.001). The levels of glucose deprivation-induced cell viability were 70.9% (IQR: 66.3–77.1) in the T2DM group and 87.8% (IQR: 83.7–90.7) in the healthy control group. The difference between the two groups was statistically significant (P = 0.001). Together these results indicate that the glucose deprivation-induced glycogen degradation and viability are reduced in PBMCs of T2DM patients.
Inhibition of IRE1 modifies effect of glucose deprivation on the expression of TNFα-related genes in U87 glioma cells
I. V. Kryvdiuk1, D. O. Minchenko1,2, N. A. Hlushchak1,
O. O. Ratushna1, L. L. Karbovskyi1, O. H. Minchenko1
1Palladin Institute of Biochemistry National Academy of Sciences of Ukraine, Kyiv;
e-mail: ominchenko@yahoo.com;
2Bohomolets National Medical University, Kyiv, Ukraine
Inhibition of IRE1 (inositol requiring enzyme-1), the major signaling pathway of endoplasmic reticulum stress, significantly decreases glioma cell proliferation and tumor growth. We have studied the expression of TNFα-related genes and effect of glucose deprivation on these gene expressions in U87 glioma cells overexpressing dominant-negative IRE1 defective in both kinase and endonuclease (dn-IRE1) activity of IRE1 with hopes of elucidating its contribution to IRE1 mediated glioma growth. We have demonstrated that glucose deprivation condition leads to down-regulation of the expression of TNFRSF11B, TNFRSF1A, TNFRSF10D/TRAILR4, and LITAF genes and up-regulation of TNFRSF10B/TRAILR2/DR5 gene at the mRNA level in control glioma cells. At the same time, the expression of TNFRSF21/DR6, TNFAIP1, TNFAIP3, TRADD, and CD70/TNFSF7 genes in control glioma cells is resistant to glucose deprivation condition. The inhibition of IRE1 modifies the effect of glucose deprivation on LITAF, TNFRSF21, TNFRSF11B, and TRADD gene expressions and induces sensitivity to glucose deprivation condition the expression of TNFRSF10B, TNFRSF1A, and CD70 genes. We have also demonstrated that the expression of all studied genes is affected in glioma cells by inhibition of IRE1, except TNFRSF1A gene, as compared to control glioma cells. Moreover, the changes in the expression of TNFRSF1A, TNFRSF10D/TRAILR4, and LITAF genes induced by glucose deprivation condition have opposite orientation to that induced by inhibition of IRE1. The present study demonstrates that fine-tuning of the expression of TNFα-induced proteins and TNF receptor superfamily genes, which related to cell death and proliferation, is regulated by IRE1, an effector of endoplasmic reticulum stress, as well as depends on glucose deprivation in gene specific manner. Thus, the inhibition of kinase and endoribonuclease activity of IRE1 correlates with deregulation of TNFα-induced protein genes and TNF receptor superfamily genes in gene specific manner and thus slower the tumor growth.