Universität zu Köln

Seufert, Lisa ORCID: 0000-0003-3931-6152 (2023). Elucidating the role of Musashi RNA-binding proteins in tubular epithelial cells and acute kidney injury. PhD thesis, Universität zu Köln.

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Abstract

RNA-binding proteins (RBPs) are essential mediators of post-transcriptional gene regulation and interaction of RBPs with target RNAs fundamentally influences every step of RNA metabolism. Consequently, dysregulation and malfunctioning of several RBPs is implicated in various human diseases including cancer, muscular atrophies, neurological disorders and kidney diseases. Recently, RBPs e.g. Human antigen R or cold-inducible RNA-binding protein have been linked to acute kidney injury (AKI), a serious complication strongly associated with increased mortality in hospitalized patients. Previous data of our group identified the RBP Musashi-1 (MSI1) as highly upregulated in a mouse model of AKI. MSI1 and its family member Musashi-2 (MSI2) are evolutionarily conserved RBPs, which have been studied extensively for their role in governing stem cell maintenance in the blood and nervous system. Unsurprisingly, both Musashi proteins are dysregulated in multiple forms of cancer, implicated in several neurodegenerative diseases and play a role in viral replication in the human body. The role of Musashi proteins in general kidney physiology and AKI however remain elusive. This work shows that MSI1, but not MSI2, is highly expressed in necrotic tubules at the cortico-medullary border in kidneys after ischemia reperfusion injury. Moreover, both Musashi proteins closely interact with a network of stress granule proteins, and oxidative stress causes robust localization of MSI1 and MSI2 in stress granules in tubular epithelial cells. In line with their function as RBPs, MSI1 and MSI2 bind to a common set of proteins involved in mRNA metabolism, translation and complex formation in tubular epithelial cells. While MSI1 interacts with 417 proteins in tubular epithelial cells, the interactome of MSI2 only consists of 296 proteins. Within this study RNA interactors of both Musashi proteins in tubular epithelial cells were characterized and it was shown that MSI1 and MSI2 bind to a high number of RNA binding sites (17922/17399), as well as similar target regions (3’UTRs) and binding motifs (UAG). Moreover, MSI1 (5264 identified RNA targets) and MSI2 (5318 RNA targets) interact with 4207 common transcripts in tubular epithelial cells. Induction of oxidative stress altered binding site and binding region preferences of both Musashi proteins and influenced in particular the composition of the MSI1 RNA interactome in tubular epithelial cells. These findings implicate that both Musashi proteins engage in similar ribonucleoprotein complexes in tubular epithelial cells. Cellular stress induces distinctive alterations to the RNA interactome, especially of MSI1, while the protein interactome remained unaffected. Examining the relevance of individual RNA target interactions and translating these observations into mouse models will help deciphering the role of MSI1 and MSI2 in AKI. Moreover, unraveling pathophysiological mechanisms in the emerging field of RNA-protein interactions holds the promise to uncover innovative therapeutic targets, which are urgently awaited for AKI.

Item Type:	Thesis (PhD thesis)
Translated title:	Title Language Beschreibung der Rolle der RNA-bindenden Musashi Proteine in tubulären Epithelzellen und der akuten Niereninsuffizienz German
Creators:	Creators Email ORCID ORCID Put Code Seufert, Lisa lisa.seufert@uk-koeln.de orcid.org/0000-0003-3931-6152 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-710472
Date:	2 May 2023
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	CECAD - Cluster of Excellence Cellular Stress Responses in Aging-Associated Diseases
Subjects:	Natural sciences and mathematics Life sciences Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language Musashi English Acute kidney injury English RNA-binding proteins English Tubular epithelial cells English
Date of oral exam:	11 July 2023
Referee:	Name Academic Title Mueller, Roman-Ulrich Professor Schwarz, Günter Professor
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/71047