bims-polyam 2023-09-03 papers

Issue of 2023–09–03
four papers selected by
Sebastian J. Hofer, University of Graz

Plant Cell Environ. 2023 Aug 31.

Spermine deficiency shifts the balance between jasmonic acid and salicylic acid-mediated defence responses in Arabidopsis.

Chi Zhang, Kostadin E Atanasov, Ester Murillo, Vicente Vives-Peris, Jiaqi Zhao, Cuiyun Deng, Aurelio Gómez-Cadenas, Rubén Alcázar.

Polyamines are small aliphatic polycations present in all living organisms. In plants, the most abundant polyamines are putrescine (Put), spermidine (Spd) and spermine (Spm). Polyamine levels change in response to different pathogens, including Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). However, the regulation of polyamine metabolism and their specific contributions to defence are not fully understood. Here we report that stimulation of Put biosynthesis by Pst DC3000 is dependent on coronatine (COR) perception and jasmonic acid (JA) signalling, independently of salicylic acid (SA). Conversely, lack of Spm in spermine synthase (spms) mutant stimulated galactolipids and JA biosynthesis, and JA signalling under basal conditions and during Pst DC3000 infection, whereas compromised SA-pathway activation and defence outputs through SA-JA antagonism. The dampening of SA responses correlated with COR and Pst DC3000-inducible deregulation of ANAC019 expression and its key SA-metabolism gene targets. Spm deficiency also led to enhanced disease resistance to the necrotrophic fungal pathogen Botrytis cinerea and stimulated endoplasmic reticulum (ER) stress signalling in response to Pst DC3000. Overall, our findings provide evidence for the integration of polyamine metabolism in JA- and SA-mediated defence responses, as well as the participation of Spm in buffering ER stress during defence.

Keywords: Botrytis cinerea; ER stress; JA; Pseudomonas syringae; SA; coronatine; galactolipids; polyamines

DOI: https://doi.org/10.1111/pce.14706

Plants (Basel). 2023 May 15. pii: 1991. [Epub ahead of print]12(10):

Response to Cadmium Toxicity: Orchestration of Polyamines and microRNAs in Maize Plant.

Seyedeh Batool Hassani, Mojgan Latifi, Sasan Aliniaeifard, Shabnam Sohrabi Bonab, Neda Nasiri Almanghadim, Sara Jafari, Elham Mohebbifar, Anahita Ahangir, Maryam Seifikalhor, Hassan Rezadoost, Massimo Bosacchi, Anshu Rastogi, Françoise Bernard.

Cadmium (Cd) is a heavy metal that is widely contaminating the environment due to its uses in industries as corrosive reagents, paints, batteries, etc. Cd can easily be absorbed through plant roots and may have serious negative impacts on plant growth. To investigate the mechanisms utilized by plants to cope with Cd toxicity, an experiment was conducted on maize seedlings. We observed that the plant growth and photosynthetic mechanism were negatively influenced during 20 days of Cd stress. The expression levels of ornithine decarboxylase (ORDC) increased in the six seedlings under Cd exposure compared to the control. However, Cd toxicity led to an increase in putrescine (Put) content only on day 15 when compared to the control plants. In fact, with the exception of day 15, the increases in the ORDC transcript levels did not show a direct correlation with the observed increases in Put content. Spermidine and Spermine levels were reduced on day 6 by Cd application, which was parallel with suppressed Spermidine synthase gene. However, an increase in Spermidine and Spermine levels was observed on day 12 along with a significant elevation in Spermidine synthase expression. On day 6, Cd was observed to start accumulating in the root with an increase in the expression of microRNA 528; while on day 15, Cd started to be observed in the shoot part with an increase in microRNA 390 and microRNA 168. These results imply that different miRNAs may regulate polyamines (PAs) in maize under Cd toxicity, suggesting a plant-derived strategy to commit a PAs/miRNA-regulated mechanism/s in different developmental stages (time points) in response to Cd exposure.

Keywords: Zea mays L.; cadmium stress; microRNAs; photosynthesis; putrescine

DOI: https://doi.org/10.3390/plants12101991

Cell Death Dis. 2023 Aug 31. 14(8): 579

Targeted inhibition of eIF5Ahpu suppresses tumor growth and polarization of M2-like tumor-associated macrophages in oral cancer.

Jincheng Zeng, Ziyu Ye, Shihong Shi, Yanfang Liang, Qingyu Meng, Qunzhou Zhang, Anh D Le.

Eukaryotic initiation factor 5A2 (eIF5A2) is overexpressed in many types of cancer, and spermidine-mediated eIF5A hypusination (eIF5Ahpu) appears to be essential to most of eIF5A's biological functions, including its important role in regulating cancer cell proliferation, epithelial-mesenchymal transition (EMT), and cancer stem cell (CSC) properties as well as immune cell functions. Here we investigated the role of eIF5Ahpu in the growth of oral squamous cell carcinoma cells (OSCCs) and OSCC-induced polarization of M2-like tumor-associated macrophages (TAMs). TCGA dataset analysis revealed an overall upregulation in the mRNA expression of eIF5A2 and several key enzymes involved in polyamine (PA) metabolism in HNSCC, which was confirmed by Western blot and IHC studies. Blocking eIF5Ahpu by GC-7 but not the upstream key enzyme activities of PA metabolism, remarkably inhibited cell proliferation and the expression of EMT- and CSC-related genes in OSCC cells. In addition, blocking eIF5Ahpu robustly inhibited OSCC-induced M2-like TAM polarization in vitro. More Importantly, blocking eIF5Ahpu dramatically retarded tumor growth and infiltration/polarization of M2-like TAM in a syngeneic orthotopic murine tongue SCC model. Thus, eIF5Ahpu plays dual functions in regulating tumor cell growth and polarization of M2-TAMs in OSCC.

DOI: https://doi.org/10.1038/s41419-023-06109-z

Biochem Genet. 2023 Sep 01.

MiR-5189-3p Suppresses cell Proliferation, Invasion and Migration Through Targeting EIF5A2 in Laryngeal Squamous Cell Carcinoma.

Dan Lou, Qiaojing Jia, Haizhong Zhang, Jingmiao Wang, Lisha Liu, Zhichang Liu, Xiaofang Jia, Jianxing Wang, Chunguang Shan.

A growing body of evidence suggests that miR-5189-3p plays a critical role in multiple diseases. This study aimed to investigate the function of miR-5189-3p in laryngeal squamous cell carcinoma (LSCC) and explore its underlying mechanisms. qRT-PCR was designed to determine the expression levels of miR-5189-3p and eukaryotic translation initiation factor 5A2 (EIF5A2), while CCK-8 assay was performed to measure the effects of miR-5189-3p on cell proliferation. Transwell assay was performed to evaluate cell invasion as well as migration, and wound healing assay was applied to demonstrate cell migratory ability. Target gene prediction and luciferase reporter assay were developed to screen the possible target gene of miR-5189-3p, and Western blot was designed to measure EIF5A2 protein expression. MiR-5189-3p was down-regulated in LSCC tissues and cell lines. Up-regulation of miR-5189-3p notably inhibited cell proliferation, invasion, and migration in HEP2 and FADU cells. EIF5A2 was the potential downstream gene of miR-5189-3p, and overexpression of miR-5189-3p apparently reduced EIF5A2 expression. Moreover, reintroduction of EIF5A2 rescued the tumor suppressive effects of miR-5189-3p. MiR-5189-3p functions as a tumor inhibitor in LSCC progression via directly regulating EIF5A2 and may be a potential therapeutic target for LSCC.

Keywords: EIF5A2; Laryngeal carcinoma; Target; miR-5189-3p

DOI: https://doi.org/10.1007/s10528-023-10489-4