Universität zu Köln

Gronostay, Alexandra (2022). The effect of hexosamine biosynthetic pathway (HBP) activation on wound healing. PhD thesis, Universität zu Köln.

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Abstract

Wound healing is a not completely unraveled complex interplay of cells, extracellular matrix (ECM) and mediators. As ineffective wound healing is an increasing global medical and economical problem, research is highly required to develop new therapeutic strategies. The ECM consists of glycosaminoglycans (GAG) which are produced in the intracellular, ubiquitous hexosamine biosynthetic pathway (HBP). Its end product, UDP-N-acetylglucosamine (UDP- GlcNAc), is required for posttranslational modification. This project investigates the role of HBP activation in wound healing in vitro. Therefore, we tested the modulation of GlcNAc, UDP-HexNAc and hyaluronic acid (HA) by GlcNAc supplementation in both immortalized and primary murine fibroblasts and keratinocytes. Then, wound healing assays were performed in these cell types. The second part of the project focuses on the effect of HBP activation on cell proliferation potential on primary murine keratinocytes performing colony formation assays with either immortalized (NIH3T3 cell) or primary murine fibroblasts as feeder layer. HBP activation by 50 mM GlcNAc supplementation caused only a mild increase of UDP- HexNAc and HA concentration in fibroblasts, yet a significant raise in keratinocytes. Interestingly, this led to a slowing effect in keratinocyte migration and consequently slowed wound closing (HaCaT cells: 80% of the wounds in the control group closed within 72 h vs. 45% of the tested group; primary keratinocytes: 80% vs. 50%). There was no significant dose- dependent effect for GlcNAc supplementation. As HA is known to accelerate wound healing, we evaluated the effect of substrates with a similar viscosity and showed this also for dextran, being therefore a possible therapeutical strategy for chronic wounds. The second part of the project demonstrated no significant effect of 50 mM GlcNAc or 50 mM glucose on proliferative potential in keratinocytes. Surprisingly, 50 mM mannose supplementation caused a significant reduction. In conclusion, HBP activation seems to affect wound healing in vitro negatively. However, my project underlines the significance of the HBP for effective cellular function including migration and proliferation, which are required for wound healing. In the future, more experiments should be performed to unravel its complete effect and to possibly identify targets for clinical application.

Item Type:	Thesis (PhD thesis)
Translated title:	Title Language Die Auswirkung der Aktivierung des Hexosamine biosynthetic pathway auf die Wundheilung German
Creators:	Creators Email ORCID ORCID Put Code Gronostay, Alexandra UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-646228
Date:	26 October 2022
Place of Publication:	Köln
Language:	English
Faculty:	Faculty of Medicine
Divisions:	Faculty of Medicine > Biochemie
Subjects:	Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language hexosamine biosynthetic pathway English wound healing English Wundheilung German
Date of oral exam:	26 October 2022
Referee:	Name Academic Title Paulsson, M.-E. Universitätsprofessor Dr. Antebi, A. Professor Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/64622