bims-polyam 2023-05-07 papers

Issue of 2023–05–07
four papers selected by
Sebastian J. Hofer, University of Graz

Kidney Int. 2023 Apr 28. pii: S0085-2538(23)00310-1. [Epub ahead of print]

Strikingly conserved gene expression changes of polyamine regulating enzymes among various forms of acute and chronic kidney injury.

Tobias Sieckmann, Gunnar Schley, Neslihan Ögel, Simon Kelterborn, Felix J Boivin, Michael Fähling, Muhammad I Ashraf, Martin Reichel, Emilia Vigolo, Andrea Hartner, Falk-Bach Lichtenberger, Tilman Breiderhoff, Felix Knauf, Christian Rosenberger, Felix Aigner, Kai Schmidt-Ott, Holger Scholz, Karin M Kirschner.

The polyamines spermidine and spermine and their common precursor molecule putrescine are involved in tissue injury and repair. Here, we test the hypothesis that impaired polyamine homeostasis contributes to various kidney pathologies in mice during experimental models of ischemia-reperfusion, transplantation, rhabdomyolysis, cyclosporine treatment, arterial hypertension, diabetes, unilateral ureteral obstruction, high oxalate feeding, and adenine-induced injuries. We found a remarkably similar pattern in most kidney pathologies with reduced expression of enzymes involved in polyamine synthesis together with increased expression of polyamine degrading enzymes. Transcript levels of amine oxidase copper-containing 1 (Aoc1), an enzyme which catalyzes the breakdown of putrescine, were barely detectable by in situ mRNA hybridization in healthy kidneys. Aoc1 was highly expressed upon various experimental kidney injuries resulting in a significant reduction of kidney putrescine content. Kidney levels of spermine were also significantly reduced, whereas spermidine was increased in response to ischemia-reperfusion injury. Increased Aoc1 expression in injured kidneys was mainly accounted for by an Aoc1 isoform that harbors 22 additional amino acids at its N-terminus and shows increased secretion. Mice with germline deletion of Aoc1 and injured kidneys showed no decrease of kidney putrescine content; although, they displayed no overt phenotype, they had fewer tubular casts upon ischemia-reperfusion injury. Hyperosmotic stress stimulated AOC1 expression at the transcriptional and post-transcription levels in metanephric explants and kidney cell lines. AOC1 expression was also significantly enhanced after kidney transplantation in humans. These data demonstrate that the kidneys respond to various forms of injury with down-regulation of polyamine synthesis and activation of the polyamine breakdown pathway. Thus, an imbalance in kidney polyamines may contribute to various etiologies of kidney injury.

Keywords: Aoc1; TRANSLATIONAL STATEMENT; kidney injury; mRNA in situ hybridization; osmotic stress; polyamines; putrescine

DOI: https://doi.org/10.1016/j.kint.2023.04.005

Reprod Biomed Online. 2023 Mar 27. pii: S1472-6483(23)00200-6. [Epub ahead of print]

High levels of hypusinated eIF5A in leiomyoma and leiomyosarcoma pathologies: a possible novel therapeutic target.

Stefania Greco, Alessandro Zannotti, Pamela Pellegrino, Federica Giantomassi, Giovanni Delli Carpini, Mattia D'Agostino, Gaia Goteri, Andrea Ciavattini, Chiara Donati, Caterina Bernacchioni, Felice Petraglia, Anna La Teana, Pasquapina Ciarmela.

RESEARCH QUESTION: Is the hypusinated form of the eukaryotic translation initiation factor 5A (EIF5A) present in human myometrium, leiomyoma and leiomyosarcoma, and does it regulate cell proliferation and fibrosis?
DESIGN: The hypusination status of eIF5A in myometrial and leiomyoma patient-matched tissues was evaluated by immunohistochemistry and Western blotting as well as in leiomyosarcoma tissues by immunohistochemistry. Myometrial, leiomyoma and leiomyosarcoma cell lines were treated with N1-guanyl-1,7-diaminoheptane (GC-7), responsible for the inhibition of the first step of eIF5A hypunization, and the proliferation rate was determined by MTT assay; fibronectin expression was analysed by Western blotting. Finally, expression of fibronectin in leiomyosarcoma tissues was detected by immunohistochemistry.
RESULTS: The hypusinated form of eIF5A was present in all tissues examined, with an increasing trend of hypusinated eIF5A levels from normal myometrium to neoplastic benign leiomyoma up to neoplastic malignant leiomyosarcoma. The higher levels in leiomyoma compared with myometrium were confirmed by Western blotting (P = 0.0046). The inhibition of eIF5A hypusination, with GC-7 treatment at 100 nM, reduced the cell proliferation in myometrium (P = 0.0429), leiomyoma (P = 0.0030) and leiomyosarcoma (P = 0.0044) cell lines and reduced the expression of fibronectin in leiomyoma (P = 0.0077) and leiomyosarcoma (P = 0.0280) cells. The immunohistochemical staining of leiomyosarcoma tissue revealed that fibronectin was highly expressed in the malignant aggressive (central) part of the leiomyosarcoma lesion, where hypusinated eIF5A was also highly represented.
CONCLUSIONS: These data support the hypothesis that eIF5A may be involved in the pathogenesis of myometrial benign and malignant pathologies.

Keywords: fibronectin; hypusinated eIF5A; leiomyoma; leiomyosarcoma; myometrium

DOI: https://doi.org/10.1016/j.rbmo.2023.03.017

Int J Cancer. 2023 May 04.

Deoxyhypusine hydroxylase: A novel therapeutic target differentially expressed in short-term vs long-term survivors of glioblastoma.

Paula Ofek, Eilam Yeini, Gali Arad, Artem Danilevsky, Sabina Pozzi, Christian Burgos Luna, Sahar Israeli Dangoor, Rachel Grossman, Zvi Ram, Noam Shomron, Henry Brem, Thomas M Hyde, Tamar Geiger, Ronit Satchi-Fainaro.

Glioblastoma (GB) is the most aggressive neoplasm of the brain. Poor prognosis is mainly attributed to tumor heterogeneity, invasiveness and drug resistance. Only a small fraction of GB patients survives longer than 24 months from the time of diagnosis (ie, long-term survivors [LTS]). In our study, we aimed to identify molecular markers associated with favorable GB prognosis as a basis to develop therapeutic applications to improve patients' outcome. We have recently assembled a proteogenomic dataset of 87 GB clinical samples of varying survival rates. Following RNA-seq and mass spectrometry (MS)-based proteomics analysis, we identified several differentially expressed genes and proteins, including some known cancer-related pathways and some less established that showed higher expression in short-term (<6 months) survivors (STS) compared to LTS. One such target found was deoxyhypusine hydroxylase (DOHH), which is known to be involved in the biosynthesis of hypusine, an unusual amino acid essential for the function of the eukaryotic translation initiation factor 5A (eIF5A), which promotes tumor growth. We consequently validated DOHH overexpression in STS samples by quantitative polymerase chain reaction (qPCR) and immunohistochemistry. We further showed robust inhibition of proliferation, migration and invasion of GB cells following silencing of DOHH with short hairpin RNA (shRNA) or inhibition of its activity with small molecules, ciclopirox and deferiprone. Moreover, DOHH silencing led to significant inhibition of tumor progression and prolonged survival in GB mouse models. Searching for a potential mechanism by which DOHH promotes tumor aggressiveness, we found that it supports the transition of GB cells to a more invasive phenotype via epithelial-mesenchymal transition (EMT)-related pathways.

Keywords: deoxyhypusine hydroxylase (DOHH); glioblastoma; long-term survivors; proteogenomics; short-term survivors

DOI: https://doi.org/10.1002/ijc.34545