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Experimental Cell Research Nov 2019Abdominal aortic aneurysms (AAA) are characterized by matrix remodeling, elastin degradation, absence of nitric oxide (NO) signaling, and inflammation, influencing...
Abdominal aortic aneurysms (AAA) are characterized by matrix remodeling, elastin degradation, absence of nitric oxide (NO) signaling, and inflammation, influencing smooth muscle cell (SMC) phenotype and gene expression. Little is known about the biomolecular release and intrinsic biomechanics of human AAA-SMCs. NO delivery could be an attractive therapeutic strategy to restore lost functionality of AAA-SMCs by inhibiting inflammation and cell stiffening. We aim to establish the differences in phenotype and gene expression of adult human AAA-SMCs from healthy SMCs. Based on our previous study which showed benefits of optimal NO dosage delivered via S-Nitrosoglutathione (GSNO) to healthy aortic SMCs, we tested whether such benefits would occur in AAA-SMCs. The mRNA expression of three genes involved in matrix degradation (ACE, ADAMTS5 and ADAMTS8) was significantly downregulated in AAA-SMCs. Total protein and glycosaminoglycans synthesis were higher in AAA-SMCs than healthy-SMCs (p < 0.05 for AAA-vs. healthy- SMC cultures) and was enhanced by GSNO and 3D cultures (p < 0.05 for 3D vs. 2D cultures; p < 0.05 for GSNO vs. non-GSNO cases). Elastin gene expression, synthesis and deposition, desmosine crosslinker levels, and lysyl oxidase (LOX) functional activity were lower, while cell proliferation, iNOS, LOX and fibrillin-1 gene expressions were higher in AAA-SMCs (p < 0.05 between respective cases), with differential benefits from GSNO exposure. GSNO and 3D cultures reduced MMPs -2, -9, and increased TIMP-1 release in AAA-SMC cultures (p < 0.05 for GSNO vs. non-GSNO cultures). AAA-SMCs were inherently stiffer and had smoother surface than healthy SMCs (p < 0.01 in both cases), but GSNO reduced stiffness (~25%; p < 0.01) and increased roughness (p < 0.05) of both cell types. In conclusion, exogenously-delivered NO offers an attractive strategy by providing therapeutic benefits to AAA-SMCs.
Topics: Adult; Aged; Aorta; Aortic Aneurysm, Abdominal; Case-Control Studies; Cell Proliferation; Cells, Cultured; Extracellular Matrix; Gene Expression; Humans; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Nitric Oxide; Nitric Oxide Synthase Type II; Phenotype; Tissue Inhibitor of Metalloproteinase-1
PubMed: 31473210
DOI: 10.1016/j.yexcr.2019.111589 -
Journal of Clinical Medicine Jul 2019Elastin degradation is accelerated in chronic obstructive pulmonary disease (COPD) and is partially regulated by Matrix Gla Protein (MGP), via a vitamin K-dependent...
Elastin degradation is accelerated in chronic obstructive pulmonary disease (COPD) and is partially regulated by Matrix Gla Protein (MGP), via a vitamin K-dependent pathway. The aim was to assess vitamin K status in COPD as well as associations between vitamin K status, elastin degradation, lung function parameters and mortality. A total of 192 COPD patients and 186 age-matched controls were included. In addition to this, 290 COPD patients from a second independent longitudinal cohort were also included. Vitamin K status was assessed by measuring plasma inactive MGP levels and rates of elastin degradation by measuring plasma desmosine levels. Reduced vitamin K status was found in COPD patients compared to smoking controls ( < 0.0005) and controls who had never smoked ( = 0.001). Vitamin K status was inversely associated with desmosine (cohort 1: = 0.001; cohort 2: = 0.004). Only few significant associations between vitamin K status and lung function parameters were found. Mortality was higher in COPD patients within the quartile with the lowest vitamin K status compared to those within the other quartiles (hazard ratio 1.85, 95% confidence interval (CI), 1.21-2.83, = 0.005). In conclusion, we demonstrated reduced vitamin K status in COPD and an inverse association between vitamin K status and elastin degradation rate. Our results therefore suggest a potential role of vitamin K in COPD pathogenesis.
PubMed: 31357639
DOI: 10.3390/jcm8081116 -
Biomechanics and Modeling in... Feb 2020Deposition of elastin and collagen in the aorta correlates with increases in blood pressure and flow during development, suggesting that the aorta adjusts its mechanical...
Deposition of elastin and collagen in the aorta correlates with increases in blood pressure and flow during development, suggesting that the aorta adjusts its mechanical properties in response to hemodynamic stresses. Elastin knockout (Eln) mice have high blood pressure and pathological remodeling of the aorta and die soon after birth. We hypothesized that decreasing blood pressure in Eln mice during development may reduce hemodynamic stresses and alleviate pathological remodeling of the aorta. We treated Eln and Eln mice with the anti-hypertensive medication captopril throughout embryonic development and then evaluated left ventricular (LV) pressure and aortic remodeling at birth. We found that captopril treatment decreased Eln LV pressure to values near Eln mice and alleviated the wall thickening and changes in mechanical behavior observed in untreated Eln aorta. The changes in thickness and mechanical behavior in captopril-treated Eln aorta were not due to alterations in measured elastin or collagen amounts, but may have been caused by alterations in smooth muscle cell (SMC) properties. We used a constitutive model to understand how changes in stress contributions of each wall component could explain the observed changes in composite mechanical behavior. Our modeling results show that alterations in the collagen natural configuration and SMC properties in the absence of elastin may explain untreated Eln aortic behavior and that partial rescue of the SMC properties may account for captopril-treated Eln aortic behavior.
Topics: Animals; Animals, Newborn; Aorta; Biomechanical Phenomena; Blood Pressure; Captopril; Desmosine; Elastin; Extracellular Matrix Proteins; Gene Expression Regulation; Heart Rate; Heart Ventricles; Hydroxyproline; Mice, Knockout; Myocytes, Smooth Muscle; RNA, Messenger; Receptors, Angiotensin; Stress, Mechanical; Vascular Remodeling
PubMed: 31270728
DOI: 10.1007/s10237-019-01198-2 -
The FEBS Journal Sep 2019Elastin is an essential structural protein in the extracellular matrix of vertebrates. It is the core component of elastic fibers, which enable connective tissues such...
Elastin is an essential structural protein in the extracellular matrix of vertebrates. It is the core component of elastic fibers, which enable connective tissues such as those of the skin, lungs or blood vessels to stretch and recoil. This function is provided by elastin's exceptional properties, which mainly derive from a unique covalent cross-linking between hydrophilic lysine-rich motifs of units of the monomeric precursor tropoelastin. To date, elastin's cross-linking is poorly investigated. Here, we purified elastin from human tissue and cleaved it into soluble peptides using proteases with different specificities. We then analyzed elastin's molecular structure by identifying unmodified residues, post-translational modifications and cross-linked peptides by high-resolution mass spectrometry and amino acid analysis. The data revealed the presence of multiple isoforms in parallel and a complex and heterogeneous molecular interconnection. We discovered that the same lysine residues in different monomers were simultaneously involved in various cross-link types or remained unmodified. Furthermore, both types of cross-linking domains, Lys-Pro and Lys-Ala domains, participate not only in bifunctional inter- but also in intra-domain cross-links. We elucidated the sequences of several desmosine-containing peptides and the contribution of distinct domains such as 6, 14 and 25. In contrast to earlier assumptions proposing that desmosine cross-links are formed solely between two domains, we elucidated the structure of a peptide that proves a desmosine formation with participation of three Lys-Ala domains. In summary, these results provide new and detailed insights into the cross-linking process, which takes place within and between human tropoelastin units in a stochastic manner.
Topics: Amino Acid Sequence; Desmosine; Elastic Tissue; Elastin; Extracellular Matrix; Humans; Hydrophobic and Hydrophilic Interactions; Lysine; Mass Spectrometry; Molecular Structure; Peptides; Protein Isoforms; Protein Processing, Post-Translational; Skin; Tropoelastin
PubMed: 31102572
DOI: 10.1111/febs.14929 -
American Journal of Respiratory and... Aug 2019Augmentation therapy with intravenous AAT (alpha-1 antitrypsin) is the only specific therapy for individuals with pulmonary disease from AAT deficiency (AATD). The... (Clinical Trial)
Clinical Trial
Augmentation therapy with intravenous AAT (alpha-1 antitrypsin) is the only specific therapy for individuals with pulmonary disease from AAT deficiency (AATD). The recommended standard dose (SD; 60 mg/kg/wk) elevates AAT trough serum levels to around 50% of normal; however, outside of slowing emphysema progression, its effects in other clinical outcomes have not been rigorously proven. To evaluate the biological effects of normalizing AAT trough levels with double-dose (DD) therapy (120 mg/kg/wk) in subjects with AATD already receiving SD therapy. Clinically stable subjects were evaluated after 4 weeks of SD therapy, followed by 4 weeks of DD therapy, and 4 weeks after return to SD therapy. At the end of each phase, BAL fluid (BALF) and plasma samples were obtained. DD therapy increased trough AAT levels to normal and, compared with SD therapy, reduced serine protease activity in BALF (elastase and cathepsin G), plasma elastase footprint (Aα-Val), and markers of elastin degradation (desmosine/isodesmosine) in BALF. DD therapy also further downregulated BALF ILs and cytokines including Jak-STAT (Janus kinases-signal transducer and activator of transcription proteins), TNFα (tumor necrosis factor-α), and T-cell receptor signaling pathways, cytokines involved in macrophage migration, eosinophil recruitment, humoral and adaptive immunity, neutrophil activation, and cachexia. On restarting SD after DD treatment, a possible carryover effect was seen for several biological markers. Subjects with AATD on SD augmentation therapy still exhibit inflammation, protease activity, and elastin degradation that can be further improved by normalizing AAT levels. Higher AAT dosing than currently recommended may lead to enhanced clinical benefits and should be explored further.Clinical trial registered with www.clinicaltrials.gov (NCT01669421).
Topics: Adolescent; Adult; Aged; Dose-Response Relationship, Drug; Feasibility Studies; Female; Humans; Male; Middle Aged; Pilot Projects; Prospective Studies; Pulmonary Disease, Chronic Obstructive; Trypsin Inhibitors; Young Adult; alpha 1-Antitrypsin; alpha 1-Antitrypsin Deficiency
PubMed: 30965011
DOI: 10.1164/rccm.201901-0010OC