bims-mecosi 2022-12-11 papers

Issue of 2022‒12‒11
three papers selected by
Verena Kohler

Int J Cardiol. 2022 Dec 05. pii: S0167-5273(22)01873-3. [Epub ahead of print]

Ferulic acid attenuates high glucose-induced MAM alterations via PACS2/IP3R2/FUNDC1/VDAC1 pathway activating proapoptotic proteins and ameliorates cardiomyopathy in diabetic rats.

P Salin Raj, Anupama Nair, M R Preetha Rani, K Rajankutty, S Ranjith, K G Raghu.

BACKGROUND: Diabetic cardiomyopathy (DCM) is one of the severe complications of diabetes with no known biomarkers for early detection. Mitochondria-associated endoplasmic reticulum membranes (MAM) are less studied subcellular targets but an emerging area for exploration in metabolic disorders including DCM. We herein studied the role of MAMs and downstream mitochondrial functions in DCM. We also explored the efficacy of ferulic acid (FeA) against DCM via modulation of MAM and its associated signaling pathway.METHODS: The H9c2 cardiomyoblast cells were incubated with high d-glucose for 48 h to create a high glucose ambience in vitro. The expression of various critical proteins of MAM, mitochondrial function, oxidative phosphorylation (OxPhos) and the genesis of apoptosis were examined. The rats fed with high fat/high fructose/streptozotocin (single dose, i.p.) were used as a diabetic model and analyzed the insulin resistance and markers of cardiac hypertrophy and apoptosis.
RESULTS: High glucose conditions caused the upregulation of MAM formation via PACS2, IP3R2, FUNDC1, and VDAC1 and decreased mitochondrial biogenesis, fusion and OxPhos. The upregulation of mitochondria-driven SMAC-HTRA2-ARTS-XIAP apoptosis and other cell death pathways indicates their critical roles in the genesis DCM at the molecular level. The diabetic rats also showed cardiomyopathy with increased heart mass index, TNNI3K, troponin, etc. FeA effectively prevented the high glucose-induced MAM alterations and associated cellular anomalies both in vitro and in vivo.
CONCLUSION: High glucose-induced MAM distortion and subsequent mitochondrial dysfunctions act as the stem of cardiomyopathy. MAM could be explored as a potential target to treat diabetic cardiomyopathy. Also, the FeA could be an attractive nutraceutical agent for diabetic cardiomyopathy.

Keywords: Apoptosis; Diabetic cardiomyopathy; Ferulic acid; MAM; Mitochondrial dynamics; OxPhos

DOI: https://doi.org/10.1016/j.ijcard.2022.12.003

Nature. 2022 Dec 07.

CLSTN3β enforces adipocyte multilocularity to facilitate lipid utilization.

Multilocular adipocytes are a hallmark of thermogenic adipose tissue1,2, but the factors that enforce this cellular phenotype are largely unknown. Here, we show that an adipocyte-selective product of the Clstn3 locus (CLSTN3β) present in only placental mammals facilitates the efficient use of stored triglyceride by limiting lipid droplet (LD) expansion. CLSTN3β is an integral endoplasmic reticulum (ER) membrane protein that localizes to ER-LD contact sites through a conserved hairpin-like domain. Mice lacking CLSTN3β have abnormal LD morphology and altered substrate use in brown adipose tissue, and are more susceptible to cold-induced hypothermia despite having no defect in adrenergic signalling. Conversely, forced expression of CLSTN3β is sufficient to enforce a multilocular LD phenotype in cultured cells and adipose tissue. CLSTN3β associates with cell death-inducing DFFA-like effector proteins and impairs their ability to transfer lipid between LDs, thereby restricting LD fusion and expansion. Functionally, increased LD surface area in CLSTN3β-expressing adipocytes promotes engagement of the lipolytic machinery and facilitates fatty acid oxidation. In human fat, CLSTN3B is a selective marker of multilocular adipocytes. These findings define a molecular mechanism that regulates LD form and function to facilitate lipid utilization in thermogenic adipocytes.

DOI: https://doi.org/10.1038/s41586-022-05507-1

Front Plant Sci. 2022 ;13 1041733

Transcriptomic and metabolomic analyses reveal the antifungal mechanism of the compound phenazine-1-carboxamide on Rhizoctonia solani AG1IA.

Ya Zhang, Qiufeng Li, Chong Wang, Shuangqing Liu.

To explore the molecular mechanisms of the antifungal compound phenazine-1-carboxamide (PCN) inhibits Rhizoctonia solani and discover potential targets of action, we performed an integrated analysis of transcriptome and metabolome in R. solani mycelium by whether PCN treating or not. A total of 511 differentially expressed genes (DEGs) were identified between the PCN treatment and control groups. The fluorescence-based quantitative PCR (qPCR) got the accordant results of the gene expression trends for ten randomly selected DEGs. The Gene Ontology (GO) enrichment analysis revealed that fatty acid metabolic process, fatty acid oxidation, and lipid oxidation were among the most enriched in the biological process category, while integral component of membrane, plasma membrane, and extracellular region were among the most enriched in the cellular component category and oxidoreductase activity, cofactor binding, and coenzyme binding were among the most enriched in the molecular function category. KEGG enrichment analysis revealed the most prominently enriched metabolic pathways included ATP-binding cassette (ABC) transporters, nitrogen metabolism, aminobenzoate degradation. The DEGs related functions of cellular structures, cell membrane functions, cellular nutrition, vacuole-mitochondrion membrane contact site and ATPase activity, pH, anti-oxidation, were downregulated. A total of 466 differential metabolites were found between the PCN treatment and control groups after PCN treatment. KEGG enrichment found purine, arachidonic acid, and phenylpropanoid biosynthesis pathways were mainly affected. Further results proved PCN decreased the mycelial biomass and protein content of R. solani, and superoxide dismutase (SOD) activity reduced while peroxidase (POD) and cytochrome P450 activities increased. The molecule docking indicted that NADPH nitrite reductase, ATP-binding cassette transporter, alpha/beta hydrolase family domain-containing protein, and NADPH-cytochrome P450 reductase maybe the particular target of PCN. In conclusion, the mechanisms via which PCN inhibits R. solani AG1IA may be related to cell wall damage, cell membrane impairment, intracellular nutrient imbalance, disturbed antioxidant system, and altered intracellular pH, which laid foundation for the further new compound designing to improve antifungal efficacy.

Keywords: Rhizoctonia solani; combined analysis; differential genes; differential metabolites; metabolome; phenazine-1-carboxamide; transcriptome

DOI: https://doi.org/10.3389/fpls.2022.1041733