Faculty Opinions recommendation of Trpv1 reporter mice reveal highly restricted brain distribution and functional expression in arteriolar smooth muscle cells.

Following vascular injury medial smooth muscle cells dedifferentiate and migrate through the internal elastic lamina where they form a neointima. The goal of the current study was to identify changes in gene expression that occur before the development of neointima and are associated with the early response to injury. Vascular injury was induced in C57BL/6 mice and in Myh11-creER(T2) mTmG reporter mice by complete ligation of the left carotid artery. Reporter mice were used to visualize cellular changes in the injured vessels. Total RNA was isolated from control carotid arteries or from carotid arteries 3 days following ligation of C57BL/6 mice and analyzed by Affymetrix microarray and quantitative RT-PCR. This analysis revealed decreased expression of mRNAs encoding smooth muscle-specific contractile proteins that was accompanied by a marked increase in a host of mRNAs encoding inflammatory cytokines following injury. There was also marked decrease in molecules associated with BMP, Wnt, and Hedgehog signaling and an increase in those associated with B cell, T cell, and macrophage signaling. Expression of a number of noncoding RNAs were also altered following injury with microRNAs 143/145 being dramatically downregulated and microRNAs 1949 and 142 upregulated. Several long noncoding RNAs showed altered expression that mirrored the expression of their nearest coding genes. These data demonstrate that following carotid artery ligation an inflammatory cascade is initiated that is associated with the downregulation of coding and noncoding RNAs that are normally required to maintain smooth muscle cells in a differentiated state.

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Increased amplitude of inward rectifier K+ currents with advanced age in smooth muscle cells of murine superior epigastric arteries

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00679.2016 ◽

2017 ◽

Vol 312 (6) ◽

pp. H1203-H1214 ◽

Cited By ~ 6

Author(s):

Sebastien Hayoz ◽

Jessica Pettis ◽

Vanessa Bradley ◽

Steven S. Segal ◽

William F. Jackson

Keyword(s):

Blood Flow ◽

Smooth Muscle ◽

Smooth Muscle Cells ◽

Muscle Cells ◽

Functional Expression ◽

Flow Regulation ◽

Advanced Age ◽

Vasomotor Tone ◽

Blood Flow Regulation ◽

Old Mice

Inward rectifier K+ channels (KIR) may contribute to skeletal muscle blood flow regulation and adapt to advanced age. Using mouse abdominal wall superior epigastric arteries (SEAs) from either young (3–6 mo) or old (24–26 mo) male C57BL/6 mice, we investigated whether SEA smooth muscle cells (SMCs) express functional KIR channels and how aging may affect KIR function. Freshly dissected SEAs were either enzymatically dissociated to isolate SMCs for electrophysiological recording (perforated patch) and mRNA expression or used intact for pressure myography. With 5 mM extracellular K+ concentration ([K+]o), exposure of SMCs to the KIR blocker Ba2+ (100 μM) had no significant effect ( P > 0.05) on whole cell currents elicited by membrane potentials spanning −120 to −30 mV. Raising [K+]o to 15 mM activated Ba2+-sensitive KIR currents between −120 and −30 mV, which were greater in SMCs from old mice than in SMCs from young mice ( P < 0.05). Pressure myography of SEAs revealed that while aging decreased maximum vessel diameter by ~8% ( P < 0.05), it had no significant effect on resting diameter, myogenic tone, dilation to 15 mM [K+]o, Ba2+-induced constriction in 5 mM [K+]o, or constriction induced by 15 mM [K+]o in the presence of Ba2+ ( P > 0.05). Quantitative RT-PCR revealed SMC expression of KIR2.1 and KIR2.2 mRNA that was not affected by age. Barium-induced constriction of SEAs from young and old mice suggests an integral role for KIR in regulating resting membrane potential and vasomotor tone. Increased functional expression of KIR channels during advanced age may compensate for other age-related changes in SEA function. NEW & NOTEWORTHY Ion channels are integral to blood flow regulation. We found greater functional expression of inward rectifying K+ channels in smooth muscle cells of resistance arteries of mouse skeletal muscle with advanced age. This adaptation to aging may contribute to the maintenance of vasomotor tone and blood flow regulation during exercise.

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GLP-1 Receptor Localization in Monkey and Human Tissue: Novel Distribution Revealed With Extensively Validated Monoclonal Antibody

Endocrinology ◽

10.1210/en.2013-1934 ◽

2014 ◽

Vol 155 (4) ◽

pp. 1280-1290 ◽

Cited By ~ 350

Author(s):

Charles Pyke ◽

R. Scott Heller ◽

Rikke K. Kirk ◽

Cathrine Ørskov ◽

Steffen Reedtz-Runge ◽

...

Keyword(s):

Monoclonal Antibody ◽

Smooth Muscle ◽

Smooth Muscle Cells ◽

Cellular Localization ◽

Glucagon Secretion ◽

Muscle Cells ◽

Functional Expression ◽

Receptor Localization ◽

Glucagon Like Peptide 1 ◽

Molecular Mode

Glucagon-like peptide 1 (GLP-1) analogs are increasingly being used in the treatment of type 2 diabetes. It is clear that these drugs lower blood glucose through an increase in insulin secretion and a lowering of glucagon secretion; in addition, they lower body weight and systolic blood pressure and increase heart rate. Using a new monoclonal antibody for immunohistochemistry, we detected GLP-1 receptor (GLP-1R) in important target organs in humans and monkeys. In the pancreas, GLP-1R was predominantly localized in β-cells with a markedly weaker expression in acinar cells. Pancreatic ductal epithelial cells did not express GLP-1R. In the kidney and lung, GLP-1R was exclusively expressed in smooth muscle cells in the walls of arteries and arterioles. In the heart, GLP-1R was localized in myocytes of the sinoatrial node. In the gastrointestinal tract, the highest GLP-1R expression was seen in the Brunner's gland in the duodenum, with lower level expression in parietal cells and smooth muscle cells in the muscularis externa in the stomach and in myenteric plexus neurons throughout the gut. No GLP-1R was seen in primate liver and thyroid. GLP-1R expression seen with immunohistochemistry was confirmed by functional expression using in situ ligand binding with 125I-GLP-1. In conclusion, these results give important new insight into the molecular mode of action of GLP-1 analogs by identifying the exact cellular localization of GLP-1R.

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Functional expression of smooth muscle-specific ion channels in TGF-β1-treated human adipose-derived mesenchymal stem cells

AJP Cell Physiology ◽

10.1152/ajpcell.00404.2012 ◽

2013 ◽

Vol 305 (4) ◽

pp. C377-C391 ◽

Cited By ~ 22

Author(s):

Won Sun Park ◽

Soon Chul Heo ◽

Eun Su Jeon ◽

Da Hye Hong ◽

Youn Kyoung Son ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Smooth Muscle ◽

Ion Channels ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Muscle Cells ◽

Functional Expression ◽

Vascular Smcs

Human adipose tissue-derived mesenchymal stem cells (hASCs) have the power to differentiate into various cell types including chondrocytes, osteocytes, adipocytes, neurons, cardiomyocytes, and smooth muscle cells. We characterized the functional expression of ion channels after transforming growth factor-β1 (TGF-β1)-induced differentiation of hASCs, providing insights into the differentiation of vascular smooth muscle cells. The treatment of hASCs with TGF-β1 dramatically increased the contraction of a collagen-gel lattice and the expression levels of specific genes for smooth muscle including α-smooth muscle actin, calponin, smooth mucle-myosin heavy chain, smoothelin-B, myocardin, and h-caldesmon. We observed Ca2+, big-conductance Ca2+-activated K+ (BKCa), and voltage-dependent K+ (Kv) currents in TGF-β1-induced, differentiated hASCs and not in undifferentiated hASCs. The currents share the characteristics of vascular smooth muscle cells (SMCs). RT-PCR and Western blotting revealed that the L-type (Cav1.2) and T-type (Cav3.1, 3.2, and 3.3), known to be expressed in vascular SMCs, dramatically increased along with the Cavβ1 and Cavβ3 subtypes in TGF-β1-induced, differentiated hASCs. Although the expression-level changes of the β-subtype BKCa channels varied, the major α-subtype BKCa channel (KCa1.1) clearly increased in the TGF-β1-induced, differentiated hASCs. Most of the Kv subtypes, also known to be expressed in vascular SMCs, dramatically increased in the TGF-β1-induced, differentiated hASCs. Our results suggest that TGF-β1 induces the increased expression of vascular SMC-like ion channels and the differentiation of hASCs into contractile vascular SMCs.

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