Hind Atta

Egypt

PROTEASOMAL REWIRING AS WJ-MSCS DIFFERENTIATE INTO INSULIN PRODUCING CELLS

Hind Atta1, Dina H. Kassem2
, Mohamed M. Kamal2 3, 4, Nadia M. Hamdy2

1 School of Life and Medical Sciences, University of Hertfordshire Hosted By Global Academic Foundation, Egypt
2Biochemistry Department, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
3 Pharmacology and Biochemistry Department, Faculty of Pharmacy, The British University in Egypt , Cairo, Egypt
4 Drug Research and Development Group, Health Research Center of Excellence, The British University in Egypt, Cairo, Egypt

Abstract

Background

Diabetes Mellitus (DM) is growing at an alarming rate, deteriorating the patient’s quality of life. Generation of insulin producing cells (IPCs) from stem cells, especially Wharton’s Jelly Mesenchymal Stem Cells (WJ-MSCs), provides great hope for diabetic patients. This study was designed to dig into the role of a potential regulator of WJ-MSCs differentiation into IPCs; the proteasome complex.

Methods

WJ-MSCs were isolated from human umbilical cord and afterwards characterized according to the criteria specified by the international society for cell and gene therapy (ISCT). WJ-MSCs were then differentiated into IPCs using a 14 days induction protocol incorporating nicotinamide and Exendin-4, and various tests were performed to confirm the IPCs identity. The mRNA expression levels of several proteasomal subunits (PSMB5, PSMB6, PSMB7, PSMD11, PSMD1, and PSMB1) and proteasome-regulating transcription factors (NFE2L1, FOXO4 and FOXO1) were determined by RT-qPCR during the differentiation steps.

Results

The isolated WJ-MSCs exhibited all MSCs characteristics, namely, fibroblastic plastic-adherence phenotype, characteristic CDs surface markers, and differentiation capacity towards adipogenic/chondrogenic mesenchymal lineages. Also, generated IPCs exhibited induced expression levels of several β-cell markers like MafA, NKX6.1, and ISL1, and positive dithizone staining compared to un-induced WJ-MSCs, as well as secretion of insulin upon glucose-stimulated-insulin-secretion (GSIS) challenge. Importantly, all proteasomal subunits showed significantly induced mRNA expression levels in differentiated IPCs compared to un-induced WJ-MSCs, most profoundly in the PSMB5, PSMD1 and PSMD11 subunits. Likewise, the proteasome-regulating transcription factors; NFE2L1, FOXO4 and FOXO1 also showed a similar pattern of elevated expression levels during differentiation compared to un-induced WJ-MSCs.

Conclusions

These findings emphasize the potential fundamental role of proteasomes during differentiation of WJ-MSCs towards IPCs and shed lights on the crucial need to further elucidate their role during differentiation of other stem cell types towards IPCs, and also towards various other lineages. These investigations can help to improve the differentiation protocols of stem cells into IPCs, and to generate mature/functional β-cells from WJ-MSCs to be used for DM regenerative therapy.