scholarly journals Mechanical stimuli and IL-13 interact at integrin adhesion complexes to regulate expression of smooth muscle myosin heavy chain in airway smooth muscle tissue

2011 ◽  
Vol 301 (3) ◽  
pp. L275-L284 ◽  
Author(s):  
Leena P. Desai ◽  
Yidi Wu ◽  
Robert S. Tepper ◽  
Susan J. Gunst
Keyword(s):  
Smooth Muscle ◽  
Protein Expression ◽  
Airway Smooth Muscle ◽  
Heavy Chain ◽  
High Load ◽  
Phenotypic Marker ◽  
Akt Activation ◽  
Muscle Tissues ◽  
Low Load ◽  
Muscle Myosin

Airway smooth muscle phenotype may be modulated in response to external stimuli under physiological and pathophysiological conditions. The effect of mechanical forces on airway smooth muscle phenotype were evaluated in vitro by suspending weights of 0.5 or 1 g from the ends of canine tracheal smooth muscle tissues, incubating the weighted tissues for 6 h, and then measuring the expression of the phenotypic marker protein, smooth muscle myosin heavy chain (SmMHC). Incubation of the tissues at a high load significantly increased expression of SmMHC compared with incubation at low load. Incubation of the tissues at a high load also decreased activation of PKB/Akt, as indicated by its phosphorylation at Ser 473. Inhibition of Akt or phosphatidylinositol-3,4,5 triphosphate-kinase increased SmMHC expression in tissues at low load but did not affect SmMHC expression at high load. IL-13 induced a significant increase in Akt activation and suppressed the expression of SmMHC protein at both low and high loads. The role of integrin signaling in mechanotransduction was evaluated by expressing a PINCH (LIM1–2) fragment in the muscle tissues that prevents the membrane localization of the integrin-binding IPP complex (ILK/PINCH/α-parvin), and also by expressing an inactive integrin-linked kinase mutant (ILK S343A) that inhibits endogenous ILK activity. Both mutants inhibited Akt activation and increased expression of SmMHC protein at low load but had no effect at high load. These results suggest that mechanical stress and IL-13 both act through an integrin-mediated signaling pathway to oppositely regulate the expression of phenotypic marker proteins in intact airway smooth muscle tissues. The stimulatory effects of mechanical stress on contractile protein expression oppose the suppression of contractile protein expression mediated by IL-13; thus the imposition of mechanical strain may inhibit changes in airway smooth muscle phenotype induced by inflammatory mediators.

The Proprotein Convertase Furin inhibits IL-13 Induced Inflammation in Airway Smooth Muscle by Regulating Integrin Associated Signaling Complexes

2021 ◽  
Author(s):  
Yidi Wu ◽  
Youliang Huang ◽  
Wenwu Zhang ◽  
Susan J. Gunst
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Inflammatory Responses ◽  
Therapeutic Potential ◽  
Proprotein Convertase ◽  
Akt Activation ◽  
Inflammatory Conditions ◽  
Muscle Tissues ◽  
Muscle Myosin

Furin is a proprotein convertase that regulates the activation and inactivation of multiple proteins including matrix metalloproteinases, integrins and cytokines. It is a serine endoprotease that localizes to the plasma membrane and can be secreted into the extracellular space. The role of furin in regulating inflammation in isolated canine airway smooth muscle tissues was investigated. The treatment of airway tissues with recombinant furin (rFurin) inhibited the activation of Akt and eotaxin secretion induced by IL-13, and it prevented the IL-13 induced suppression of smooth muscle myosin heavy chain expression. rFurin promoted a differentiated phenotype by activating β1 integrin proteins and stimulating the activation of the adhesome proteins vinculin and paxillin by talin. Activated paxillin induced the binding of Akt to β-parvin IPP (ILK, PINCH, parvin) complexes, which inhibits Akt activation. Treatment of tissues with a furin inhibitor or the depletion of endogenous furin using shRNA resulted in Akt activation and inflammatory responses similar to those induced by IL-13. Furin inactivation or IL-13 caused talin cleavage and integrin inactivation, resulting in the inactivation of vinculin and paxillin. Paxillin inactivation resulted in the coupling of Akt to α-parvin IPP complexes, which catalyze Akt activation and an inflammatory response. The results demonstrate that furin inhibits inflammation in airway smooth muscle induced by IL-13, and that the anti-inflammatory effects of furin are mediated by activating integrin proteins and integrin-associated signaling complexes that regulate Akt-mediated pathways to the nucleus. Furin may have therapeutic potential for the treatment of inflammatory conditions of the lungs and airways.

scholarly journals The Heavy-chain Stoichiometry of Smooth Muscle Myosin is a Characteristic of Smooth Muscle Tissues

1988 ◽  
Vol 41 (4) ◽  
pp. 409 ◽  
Author(s):  
Mukhallad A Mohammad ◽  
Malcolm P Sparrow
Keyword(s):  
Smooth Muscle ◽  
Heavy Chain ◽  
Relative Proportion ◽  
Sodium Dodecyl ◽  
Smooth Muscle Myosin ◽  
Human Bronchus ◽  
Heavy Chains ◽  
Tissue Extracts ◽  
Muscle Tissues ◽  
Muscle Myosin

The stoichiometry of the two heavy chains of myosin in smooth muscle was determined by electrophoresing extracts of native myosin and of dissociated myosin on sodium dodecyl sulfate (SDS) 4%-polyacrylamide gels. The slower migrating heavy chain was 3�6 times more abundant in toad stomach, 2�3 in rabbit myometrium, 2�0 in rat femoral artery, 1�3 in guinea pig ileum, 0�93 in pig trachea and 0�69 in human bronchus, than the more rapidly migrating chain. Both heavy chains were identified as smooth muscle myosin by immunoblotting using antibodies to smooth muscle and nonmuscle myosin. The unequal proportion of heavy chains suggested the possibility of native isoforms of myosin comprised of heavy-chain homodimers. To test this, native myosin extracts were electrophoresed on non-dissociating (pyrophosphate) gels. When each band was individually analysed on SDS-polyacrylamide gel the slowest was found to be filamin and the other bands were myosin in which the relative proportion of the heavy chains was unchanged from that found in the original tissue extracts. Since this is incompatible with either a heterodimeric or a homodimeric arrangement it suggests that pyrophosphate gel electrophoresis is incapable of separating putative isoforms of native myosin.

Histamine stimulates proliferation of airway smooth muscle and induces c-fos expression

1990 ◽  
Vol 259 (6) ◽  
pp. L365-L371 ◽  
Author(s):  
R. A. Panettieri ◽  
P. A. Yadvish ◽  
A. M. Kelly ◽  
N. A. Rubinstein ◽  
M. I. Kotlikoff
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Protein Expression ◽  
Myosin Heavy Chain ◽  
Airway Smooth Muscle ◽  
Heavy Chain ◽  
Thymidine Incorporation ◽  
Dependent Manner ◽  
Altered Expression ◽  
Mrna Induction

Although chronic severe asthma is characterized by increased smooth muscle mass in the airways, the physiological stimuli that promote airway smooth muscle (ASM) proliferation (hyperplasia) or increase ASM protein expression (hypertrophy) are unknown. We examined the effects of histamine, an autocoid associated with airway hyperresponsiveness, on protein synthesis, myosin heavy chain expression, and cell proliferation in cultured canine ASM cells. In confluent ASM cells, histamine significantly increased incorporation of [35S]-methionine in protein. Maintenance of the proportion of smooth muscle-specific myosin heavy chain to total myosin heavy chain suggested a nonspecific increase in contractile protein expression. DNA synthesis, as measured by [3H]thymidine incorporation, was significantly increased by histamine in a concentration-dependent manner. Cell proliferation paralleled [3H]thymidine incorporation; histamine significantly increased cell numbers at 24 and 48 h of stimulation. Because growth of mesenchymal-derived cells is associated with transcription of c-fos mRNA, we examined whether histamine altered expression of this proto-oncogene. Histamine-treated cells showed marked increases in expressions of steady-state c-fos mRNA, with a time course of mRNA induction similar to cells exposed to platelet-derived growth factor or serum, known smooth muscle and fibroblast cell mitogens. Therefore, histamine is an ASM mitogen with an action similar to other mesenchymal cell growth factors and may play a role in the hyperplasia of ASM in asthma.

Identification of a novel smooth muscle myosin heavy chain cDNA: isoform diversity in the S1 head region

1993 ◽  
Vol 264 (5) ◽  
pp. C1252-C1258 ◽  
Author(s):  
S. White ◽  
A. F. Martin ◽  
M. Periasamy
Keyword(s):  
Smooth Muscle ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Single Gene ◽  
Smooth Muscle Myosin ◽  
Head Region ◽  
Differential Distribution ◽  
Isoform Diversity ◽  
Muscle Tissues ◽  
Muscle Myosin

Smooth muscle myosin heavy chain (SMHC) isoforms, SM1 and SM2, are the products of alternative splicing from a single gene (P. Babij and M. Periasamy. J. Mol. Biol. 210: 673-679, 1989). We have previously shown that this splicing occurs at the 3'-end of the mRNA, resulting in proteins that differ at the carboxyterminal (R. Nagai, M. Kuro-o, P. Babij, and M. Periasamy. J. Biol. Chem. 264: 9734-9737, 1989). In the present study we demonstrate that additional SMHC isoform diversity occurs in the globular head region by isolating and characterizing two distinct rat SMHC cDNA (SMHC-11 = SM1B and SMHC-5 = SM1A). Sequence comparison of the two clones reveals that they are completely identical in their coding regions, except at the region encoding the 25/50 kDa junction of the myosin head, where the SM1B isoform contains an additional seven amino acids. This divergent region is located adjacent to the Mg(2+)-ATPase site, and differences in this region may be of functional importance. Ribonuclease protection analysis demonstrates that the corresponding SM1B and SM1A mRNA messages are coexpressed in all smooth muscle tissues; however, the proportion of the two mRNA present differs significantly between tissues. The SM1A-type mRNA predominates in most smooth muscle tissues, with the exception of intestine and urinary bladder, which contain greater proportions of the SM1B message. The differential distribution of these two isoforms may provide important clues toward understanding differences in smooth muscle contractile properties.

Markers of airway smooth muscle cell phenotype

1996 ◽  
Vol 270 (6) ◽  
pp. L1040-L1051 ◽  
Author(s):  
A. J. Halayko ◽  
H. Salari ◽  
X. MA ◽  
N. L. Stephens
Keyword(s):  
Smooth Muscle ◽  
Myosin Heavy Chain ◽  
Airway Smooth Muscle ◽  
Heavy Chain ◽  
Cytoskeletal Proteins ◽  
Cell Phenotype ◽  
Airway Smooth Muscle Cells ◽  
Mrna Levels ◽  
Alpha Actin ◽  
Muscle Myosin

Airway smooth muscle plays a principal role in the pathogenesis of asthma. Primary cultures are being used to investigate airway myocyte proliferation and cellular pathways regulating contraction. Airway smooth muscle cells (SMC) modulate from a contractile to a noncontractile phenotype in culture, but no systematic study of the concomitant changes in expression of cytocontractile and cytoskeletal proteins has been reported. We measured temporal changes in protein marker expression of canine tracheal SMC in primary culture, using specific antibodies and cDNA probes. Immunoblot analysis revealed that when cells became proliferative after 5 days of culture, the content of smooth muscle myosin heavy chain (sm-MHC), calponin, sm-alpha-actin, and desmin diminished by > 75%; myosin light chain kinase, h-caldesmon, and beta-tropomyosin had also decreased significantly (P < 0.05). Northern blots revealed that mRNA levels for sm-MHC and sm-alpha-actin were also significantly reduced in proliferative SMC. Conversely, immunoblotting demonstrated the content of non-muscle myosin heavy chain, l-caldesmon, vimentin, alpha/beta-protein kinase C (PKC), and CD44 homing cellular adhesion molecule (HCAM) increased one- to sixfold as cells became proliferative. The content of sm-MHC and sm-alpha-actin protein increased after confluence, suggesting that cultured airway SMC are capable of phenotypic plasticity. Marker protein contents were also compared, by immunoblot assay, between SMC dissociated from trachealis or pulmonary arterial media. Cytocontractile protein content was higher in the trachea, which shortens faster than the pulmonary artery. The identification of these markers provides tools for assessing the phenotype of airway SMC in culture and the airways of asthmatic patients.

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