Smooth Muscle Studies Using Gene-Altered Mouse Models: A Users’ Guide

Sutliff, Roy L.; Rutgeerts, Paul

doi:10.1007/978-1-4615-1653-8_20

Cited by 9 publications

(8 citation statements)

References 43 publications

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“…Aortae were excised, placed in ice-cold physiological saline solution, debrided of loose fat and connective tissue, and prepared for measurement of isometric force as previously described [ 33 – 35 ]. The thoracic segment of aorta was dissected free from surrounding tissues and cut into rings of 2 mm in length.…”

Section: Methodsmentioning

confidence: 99%

Differential Mitochondrial Adaptation in Primary Vascular Smooth Muscle Cells from a Diabetic Rat Model

Keller

Knaub

McClatchey

et al. 2016

Oxidative Medicine and Cellular Longevity

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Diabetes affects more than 330 million people worldwide and causes elevated cardiovascular disease risk. Mitochondria are critical for vascular function, generate cellular reactive oxygen species (ROS), and are perturbed by diabetes, representing a novel target for therapeutics. We hypothesized that adaptive mitochondrial plasticity in response to nutrient stress would be impaired in diabetes cellular physiology via a nitric oxide synthase- (NOS-) mediated decrease in mitochondrial function. Primary smooth muscle cells (SMCs) from aorta of the nonobese, insulin resistant rat diabetes model Goto-Kakizaki (GK) and the Wistar control rat were exposed to high glucose (25 mM). At baseline, significantly greater nitric oxide evolution, ROS production, and respiratory control ratio (RCR) were observed in GK SMCs. Upon exposure to high glucose, expression of phosphorylated eNOS, uncoupled respiration, and expression of mitochondrial complexes I, II, III, and V were significantly decreased in GK SMCs (p < 0.05). Mitochondrial superoxide increased with high glucose in Wistar SMCs (p < 0.05) with no change in the GK beyond elevated baseline concentrations. Baseline comparisons show persistent metabolic perturbations in a diabetes phenotype. Overall, nutrient stress in GK SMCs caused a persistent decline in eNOS and mitochondrial function and disrupted mitochondrial plasticity, illustrating eNOS and mitochondria as potential therapeutic targets.

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Section: Methodsmentioning

confidence: 99%

Differential Mitochondrial Adaptation in Primary Vascular Smooth Muscle Cells from a Diabetic Rat Model

Keller

Knaub

McClatchey

et al. 2016

Oxidative Medicine and Cellular Longevity

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“…Aortae or bladders were excised, placed in ice-cold physiological saline solution, and debrided of loose fat and connective tissue, and prepared for measurement of isometric force as previously described in detail (2,33). Matched littermate mice between 8 and 14 wk old were euthanized by CO2 asphyxiation.…”

Section: Methodsmentioning

confidence: 99%

Expression and function of COOH-terminal myosin heavy chain isoforms in mouse smooth muscle

Martin¹,

Bhatti²,

Pyne‐Geithman³

et al. 2007

American Journal of Physiology-Cell Physiology

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Isoforms of the smooth muscle myosin motor, SM1 and SM2, differ in length at the carboxy terminal tail region. Their proportion changes with development, hormonal status and disease, but their function is unknown. We developed mice carrying the myosin heavy chain (MyHC) transgenes SM1, cMyc-tagged SM1, SM2, and V5-tagged SM2, and all transgenes corresponded to the SMa NH(2)-terminal isoform. Transgene expression was targeted to smooth muscle by the smooth muscle alpha-actin promoter. Immunoblot analysis showed substantial expression of the cMyc-tagged SM1 and V5-tagged SM2 MyHC protein in aorta and bladder and transgene mRNA was expressed in mice carrying unlabeled SM1 or SM2 transgenes. Despite significant protein expression of tagged MyHCs we found only small changes in the SM1:SM2 protein ratio. Significant changes in functional phenotype were observed in mice carrying unlabeled SM1 or SM2 transgenes. Force in aorta and bladder was increased (72 +/- 14%, 92 +/- 11%) in SM1 and decreased to 57 +/- 1% and 80 +/- 3% in SM2 transgenic mice. SM1 transgenic bladders had faster (1.8 +/- 0.3 s) and SM2 slower (7.1 +/- 0.5 s) rates of force redevelopment following a rapid step shortening. We hypothesize that small changes in the SM1:SM2 ratio could be amplified if they are associated with changes in thick filament assembly and underlie the altered contractility. These data provide evidence indicating an in vivo function for the COOH-terminal isoforms of smooth muscle myosin and suggest that the SM1:SM2 ratio is tightly regulated in smooth muscle tissues.

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“…The rings were then immersed in a physiologic saline solution (118 mM NaCl, 4.73 mM KCl, 1.2 mM MgCl 2 , 0.026 mM EDTA, 1.2 mM KH 2 PO 4 , 2.5 mM CaCl 2 , 25 mM NaH 2 CO 3 , and 11 mM glucose) maintained at 37°C and bubbled with 95% O 2 , 5% CO 2 to maintain a pH of 7.4. Each tracheal ring was stretched to a tension of 5 millinewtons, an optimal passive tension for maximizing active force (27). After a 20-min equilibration period, contraction/relaxation cycles with 10 M acetylcholine were performed until consistent forces were observed.…”

Section: Methodsmentioning

confidence: 99%

Transgenic Overexpression of β2-Adrenergic Receptors in Airway Smooth Muscle Alters Myocyte Function and Ablates Bronchial Hyperreactivity

McGraw¹,

Forbes²,

Kramer³

et al. 1999

Journal of Biological Chemistry

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␤ 2 -Adrenergic receptors (␤ 2 AR) act to relax airway smooth muscle and can serve to counteract hyperresponsiveness, although the effect may not be ablative even in the presence of exogenous agonist. Within this signaling cascade that ultimately transduces smooth muscle relaxation, a significant "spare receptor" pool has been hypothesized to be present in the airway. In order to modify the relationship between ␤ 2 AR and downstream effectors, transgenic mice (TG) were created overexpressing ␤ 2 AR ϳ75-fold in airway smooth muscle using a mouse smooth muscle ␣-actin promoter. While >90% of these receptors were expressed on the smooth muscle cell surface, the percentage of receptors able to form the agonist-promoted high affinity complex was less than that found with nontransgenic (NTG) cells (R H ‫؍‬ 18 versus 36%). Nevertheless, ␤ 2 AR signaling was found to be enhanced. Intact airway smooth muscle cells from TG had basal cAMP levels that were greater than NTG cells. A marked increase in agonist-stimulated cAMP levels was found in the TG (ϳ200% stimulation over basal) compared with NTG (ϳ50% over basal) cells. Adenylyl cyclase studies gave similar results and also showed a 10-fold lower EC 50 for TG cells. Tracheal rings from TG mice that were precontracted with acetylcholine had an enhanced responsiveness (relaxation) to ␤-agonist, with a 60-fold decrease in the ED 50 , indicating that the enhanced signaling imposed by overexpression results in an increase in the coordinated function of the intact airway cells. In vivo studies showed a significantly blunted airway resistance response to the inhaled bronchoconstrictor methacholine in the TG mice. Indeed, with ␤-agonist pretreatment, the TG mice displayed no response whatsoever to methacholine. These results are consistent with ␤ 2 AR being the limiting factor in the transduction system. Increases in the initial component of this transduction system (the ␤ 2 AR) are sufficient to markedly alter signaling and airway smooth muscle function to the extent that bronchial hyperresponsiveness is ablated, consistent with an antiasthma phenotype.

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Smooth Muscle Studies Using Gene-Altered Mouse Models: A Users’ Guide

Cited by 9 publications

References 43 publications

Differential Mitochondrial Adaptation in Primary Vascular Smooth Muscle Cells from a Diabetic Rat Model

Differential Mitochondrial Adaptation in Primary Vascular Smooth Muscle Cells from a Diabetic Rat Model

Expression and function of COOH-terminal myosin heavy chain isoforms in mouse smooth muscle

Transgenic Overexpression of β2-Adrenergic Receptors in Airway Smooth Muscle Alters Myocyte Function and Ablates Bronchial Hyperreactivity

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