Upregulation of ALOX12-12-HETE pathway impairs AMPK-dependent modulation of vascular metabolism in ApoE/LDLR-/- mice.

Mitochondrial dysfunction and 12-lipoxygenase (ALOX12)-derived 12(S)-HETE production have been associated with vascular inflammation and the pathogenesis of atherosclerosis. However, the role of ALOX12 in regulating vascular energy metabolism in vascular inflammation has not been studied to date. Using mitochondrial and glycolysis functional profiling with the Seahorse extracellular flux analyzer, metabolipidomics, and proteomic analysis (LC-MS/MS), we characterized alterations in vascular energy metabolism in 2- and 6-month-old ApoE/LDLR-/- vs. control C57BL/6 mice. We identified that aorta of 6-month-old ApoE/LDLR-/- mice displayed compromised mitochondrial metabolism manifested by the reduced expression of mitochondrial enzymes, impaired mitochondrial respiration, and consequently diminished respiratory reserve capacity. An increased flux through the glycolysis/lactate shuttle, the hexosamine biosynthetic pathway (HBP), and the pentose phosphate pathway (PPP) was also recognized. Interestingly, ALOX12-12-HETE was the most upregulated axis in eicosanoid metabolism and histological examinations indicated that ApoE/LDLR-/- mice showed increased aortic expression of ALOX12, particularly in early atherosclerotic plaque areas. Remarkably, the joint blocking of ALOX12 and activation of AMPK, but not AMPK activation alone, resulted in the reprogramming of vascular metabolism, with improved mitochondrial respiration and suppressed auxiliary pathways (HBP, PPP, itaconate shunt). In conclusion, excessive activation of the ALOX12-12-HETE pathway in vascular inflammation in early atherosclerosis inhibits AMPK-dependent regulation of vascular metabolism. Consequently, ALOX12 may represent a novel target to boost impaired vascular mitochondrial function in pro-atherosclerotic vascular inflammation.

Epigenetic clock in the aorta and age-related endothelial dysfunction in mice.

While epigenetic age (EA) of mouse blood can be determined using DNA methylation analysis at three CpG sites in the Prima1, Hsf4 and Kcns1 genes it is not known whether this approach is useful for predicting vascular biological age. In this study we validated the 3-CpG estimator for age prediction in mouse blood, developed a new predictive model for EA in mouse aorta, and assessed whether epigenetic age acceleration (EAA) measured with blood and aorta samples correlates with age-dependent endothelial dysfunction. Endothelial function was characterized in vivo by MRI in 8-96-week-old C57BL/6 mice. Arterial stiffness was measured by USG-doppler. EA-related changes within 41 CpG sites in Prima1, Kcns1 and Hsf4 loci, were analyzed in the aorta and blood using bisulfite amplicon high-throughput sequencing. Progressive age-dependent endothelial dysfunction and changes in arterial stiffness were observed in 36-96-week-old C57BL/6 mice. Methylation levels of the investigated loci correlated with chronological age in blood and the aorta. The new model for EA estimation in aorta included three cytosines located in the Kcns1 and Hsf4, explained R2 = 87.8% of the variation in age, and predicted age with an mean absolute error of 9.6 weeks in the independent test set. EAA in the aorta was associated with endothelial dysfunction in the abdominal aorta and femoral artery what was consistent with the EAA direction estimated in blood samples. The rate of vascular biological ageing in mice, reflected by the age-dependent systemic endothelial dysfunction, could be estimated using DNA methylation measurements at three loci in aorta and blood samples.

Chymase-independent vascular Ang-(1-12)/Ang II pathway and TXA2 generation are involved in endothelial dysfunction in the murine model of heart failure.

The angiotensin (Ang)-(1-12)/Ang II pathway contributes to cardiac pathology. However, its involvement in the development of peripheral endothelial dysfunction associated with heart failure (HF) remains unknown. Therefore, this study aimed to characterise the effect of exogenous Ang-(1-12) and its conversion to Ang II on endothelial function using the murine model of HF (Tgαq*44 mice), focusing on the role of chymase and vascular-derived thromboxane A2 (TXA2). Ex vivo myographic assessments of isolated aorta showed impaired endothelium-dependent vasodilation in late-stage HF in 12-month-old Tgαq*44 mice. However, endothelium-dependent vasodilation was fully preserved in the early stage of HF in 4-month-old Tgαq*44 mice and 4- and 12-month-old FVB control mice. Ang-(1-12) impaired endothelium-dependent vasodilation in 4- and 12-month-old Tgαq*44 mice, that was associated with increased Ang II production. The chymase inhibitor chymostatin did not inhibit this response. Interestingly, TXA2 production reflected by TXB2 measurement was upregulated in response to Ang-(1-12) and Ang II in aortic rings isolated from 12-month-old Tgαq*44 mice but not from 4-month-old Tgαq*44 mice or age-matched FVB mice. Furthermore, in vivo magnetic resonance imaging showed that Ang-(1-12) impaired endothelium-dependent vasodilation in the aorta of Tgαq*44 mice and FVB mice. However, this response was inhibited by angiotensin I converting enzyme (ACE) inhibitor; perindopril, angiotensin II receptor type 1 (AT1) antagonist; losartan and TXA2 receptor (TP) antagonist-picotamide in 12-month-old-Tgαq*44 mice only. In conclusion, the chymase-independent vascular Ang-(1-12)/Ang II pathway and subsequent TXA2 overactivity contribute to systemic endothelial dysfunction in the late stage of HF in Tgαq*44 mice. Therefore, the vascular TXA2 receptor represents a pharmacotherapeutic target to improve peripheral endothelial dysfunction in chronic HF.

Functional deterioration of vascular mitochondrial and glycolytic capacity in the aortic rings of aged mice.

Vascular ageing is associated with increased arterial stiffness and cardiovascular mortality that might be linked to altered vascular energy metabolism. The aim of this study was to establish a Seahorse XFe96 Analyzer-based methodology for the reliable, functional assessment of mitochondrial respiration and glycolysis in single murine aortic rings and to validate this functional assay by characterising alterations in vascular energy metabolism in aged mice. Healthy young and old C57BL/6 mice were used for the analyses. An optimised setup consisting of the Seahorse XFe96 Analyzer and Seahorse Spheroid Microplates was applied for the mitochondrial stress test and the glycolysis stress test on the isolated murine aortic rings, supplemented with analysis of NAD content in the aorta. To confirm the age-dependent stiffness of the vasculature, pulse wave velocity was measured in vivo. In addition, the activity of vascular nitric oxide synthase and vascular wall morphology were analysed ex vivo. The vascular ageing phenotype in old mice was confirmed by increased aortic stiffness, vascular wall remodelling, and nitric oxide synthase activity impairment. The rings of the aorta taken from old mice showed changes in vascular energy metabolism, including impaired spare respiratory capacity, maximal respiration, glycolysis, and glycolytic capacity, as well as a fall in the NAD pool. In conclusion, optimised Seahorse XFe96-based analysis to study energy metabolism in single aortic rings of murine aorta revealed a robust impairment of functional vascular respiratory and glycolytic capacity in old mice linked to NAD deficiency that coincided with age-related aortic wall remodelling and stiffness.

Non-targeting control for MISSION shRNA library silences SNRPD3 leading to cell death or permanent growth arrest.

In parallel with the expansion of RNA interference (RNAi) techniques, accumulating evidence indicates that RNAi analyses might be seriously biased due to the off-target effects of gene-specific short hairpin RNAs (shRNAs). Our findings indicated that off-target effects of non-targeting shRNA comprise another source of misinterpreted shRNA-based data. We found that SHC016, which is one of two non-targeting shRNA controls for the MISSION (commercialized TRC) library, exerts deleterious effects that lead to elimination of the shRNA-coding cassette from the genomes of cultured murine and human cells. Here, we used a lentiviral vector with inducible SHC016 expression to confirm that this shRNA induces apoptosis in murine cells and senescence or mitotic catastrophe depending on the p53 status in human tumor cells. We identified the core spliceosomal protein, small nuclear ribonucleoprotein Sm D3 (SNRPD3), as a major SHC016 target in several cell lines and confirmed that CRISPRi knockdown of SNRPD3 mimics the effects of SHC016 expression in A549 and U251 cells. The overexpression of SNRPD3 rescued U251 cells from SHC016-induced mitotic catastrophe. Our findings disqualified non-targeting SHC016 shRNA and added a new premise to the discussion about the sources of uncertainty in RNAi results.

ß-Adrenergic Stimulation Induces Histone Deacetylase 5 (HDAC5) Nuclear Accumulation in Cardiomyocytes by B55α-PP2A-Mediated Dephosphorylation.

BACKGROUND: Class IIa histone deacetylase (HDAC) isoforms such as HDAC5 are critical signal-responsive repressors of maladaptive cardiomyocyte hypertrophy, through nuclear interactions with transcription factors including myocyte enhancer factor-2. ß-Adrenoceptor (ß-AR) stimulation, a signal of fundamental importance in regulating cardiac function, has been proposed to induce both phosphorylation-independent nuclear export and phosphorylation-dependent nuclear accumulation of cardiomyocyte HDAC5. The relative importance of phosphorylation at Ser259/Ser498 versus Ser279 in HDAC5 regulation is also controversial. We aimed to determine the impact of ß-AR stimulation on the phosphorylation, localization, and function of cardiomyocyte HDAC5 and delineate underlying molecular mechanisms. METHODS AND RESULTS: A novel 3-dimensional confocal microscopy method that objectively quantifies the whole-cell nuclear/cytoplasmic distribution of green fluorescent protein tagged HDAC5 revealed the ß-AR agonist isoproterenol to induce ß1-AR-mediated and protein kinase A-dependent HDAC5 nuclear accumulation in adult rat cardiomyocytes, which was accompanied by dephosphorylation at Ser259/279/498. Mutation of Ser259/Ser498 to Ala promoted HDAC5 nuclear accumulation and myocyte enhancer factor-2 inhibition, whereas Ser279 ablation had no such effect and did not block isoproterenol-induced nuclear accumulation. Inhibition of the Ser/Thr phosphatase PP2A blocked isoproterenol-induced HDAC5 dephosphorylation. Co-immunoprecipitation revealed a specific interaction of HDAC5 with the PP2A targeting subunit B55α, as well as catalytic and scaffolding subunits, which increased >3-fold with isoproterenol. Knockdown of B55α in neonatal cardiomyocytes attenuated isoproterenol-induced HDAC5 dephosphorylation. CONCLUSIONS: ß-AR stimulation induces HDAC5 nuclear accumulation in cardiomyocytes by a mechanism that is protein kinase A-dependent but requires B55α-PP2A-mediated dephosphorylation of Ser259/Ser498 rather than protein kinase A-mediated phosphorylation of Ser279.

Agrobacterium-mediated transformation of polyploid cereals. The efficiency of selection and transgene expression in wheat.

Three combinations of Agrobacterium tumefaciens strains and vectors were used in the transformation of selected Polish wheat cultivars. The combinations were: two hypervirulent strains, AGL1, containing the pDM805 binary plasmid, and EHA101, containing pGAH; and the common Agro strain LBA4404, harboring the super-binary pTOK233 vector. pDM805 contained bar under the control of Ubi1 promoter, pGAH had nptII under nos, and pTOK233 had hpt under 35S. Additionally, pDM805 and pTOK233 carried the gus reporter gene under the Act1 promoter or 35S promoter, respectively. The highest selection rate was 12.6% and was obtained with EHA101(pGAH) on a kanamycin-containing medium. Sixty-five of the plants grown on that medium were PCR positive. The second best combination was LBA4404(pTOK233) and kanamycin selection, which gave an average transformation rate of 2.3%. Phosphinothricin selection gave 1.0% transformation efficiency, while hygromycin, depending on the strain/vector used, gave from 0.2 to 0.4%. PCR tests in T1 revealed that 67% of the lines showed a 3:1 segregation ratio, and 11% a 15:1 ratio, while in 22%, segregation was non-Mendelian. The high number of T0 transgenic plants containing one copy of the transgene was confirmed via Southern blot analysis. Kanamycin resistance in the T1 generation was very low; in some lines, all the progeny were kanamycin sensitive. GUS expression, only tested in young T1 plants, was in agreement with Mendelian segregation in three out of the twelve tested. The factors influencing the efficiency of selection and transgene expression are discussed in this paper.