5-HT2B Antagonism Inhibits Strain- and Cytokine-Dependent Formation of Calcific Nodules by Aortic Valve Interstitial Cells

2012 ◽  
Author(s):  
Joshua D. Hutcheson ◽  
Joseph Chen ◽  
Larisa M. Ryzhova ◽  
W. David Merryman
Keyword(s):  
Aortic Valve ◽  
Mechanical Strain ◽  
Cyclic Strain ◽  
Cell Types ◽  
Epidemiological Studies ◽  
Interstitial Cells ◽  
Nodule Formation ◽  
Type I ◽  
Tgf Β1

The progression of aortic valve (AV) disease is often characterized by the formation of calcific nodules on thickened AV leaflets, limiting the biomechanical function of the valve. In these cases, the association of extracellular Ca2+ with phosphates remaining in cellular debris within the decellularized scaffolds has been proposed to lead to the nucleation and growth of calcific nodules. In native tissue, calcification is thought to be a more active process involving AV interstitial cells (AVICs). AVICs have been shown to form nodule-like structures in vitro through differentiation to a phenotype with osteogenic character. Additionally, in vitro nodules are characterized by activated smooth muscle α-actin (αSMA) positive AVICs and high levels of apoptosis [1–2]. Mechanical strain has also been shown to influence nodule formation in excised AV leaflets [3]. Our lab has recently developed a model system that recapitulates the formation of calcific nodules in vitro [4]. AVICs treated with TGF-β1 for 24 h prior to the addition of 15% cyclic strain in a Flexcell strain system form nodules that appear to be dependent upon the initiation of AVIC activation. These observations are consistent with previous studies that have shown that αSMA expression is required for nodule formation by AVICs in static culture, with statins shown to inhibit in vitro nodule formation [1]. However, retrospective epidemiological studies have shown that these drugs may not be as effective in preventing calcific valve disease in patients [5]. Additionally, the molecular target and relevant pathways for statins in AVICs remain largely unknown. Therefore, a therapeutically relevant target to prevent AVIC activation and subsequent nodule formation is greatly needed. In this study we investigated the ability of antagonists to 5-HT2B, a receptor known to be upstream of TGF-β1, to oppose strain- and TGF-β1-induced AVIC activation and nodule formation. We also assessed the efficacy of an antagonist to a receptor, the angiotensin II type I receptor (AT1R), known to crosstalk with both 5-HT2B and TGF-β1 signaling in other cell types in inhibiting AVIC nodule formation. Our results indicate that 5-HT2B antagonism inhibits AVIC activation and nodule formation by blocking non-canonical TGF-β1 signaling, whereas AT1R antagonism does not inhibit these outcomes. We believe that the results of this study may indicate novel therapeutic targets to prevent the progression of AV calcification.

Strain and Substrate Stiffness Affect Calcium Accumulation in Aortic Valve Interstitial Cells

2011 ◽  
Author(s):  
Joshua D. Hutcheson ◽  
M. K. Sewell-Loftin ◽  
W. David Merryman
Keyword(s):  
Aortic Valve ◽  
Molecular Mechanisms ◽  
Cultured Cells ◽  
Mechanical Strain ◽  
Cell Types ◽  
Interstitial Cells ◽  
Nodule Formation ◽  
Native Tissue

The progression of aortic valve (AV) disease is often characterized by the formation of calcific nodules on thickened AV leaflets, limiting the biomechanical function of the valve. Calcification is a major problem that often leads to the failure of bioprosthetic replacement valves [1]. In these cases, the association of extracellular Ca2+ with phosphates remaining in cellular debris within the decellularized scaffolds has been proposed to lead to the nucleation and growth of Ca3(PO4)2 nodules. In native tissue, calcification is thought to be a more active process involving AV interstitial cells (AVICs). The exact molecular mechanisms that lead to the formation of these calcific nodules in native tissue remain unclear; however, AVICs have been shown to form nodule-like structures in vitro through differentiation to a phenotype with osteogenic character [2]. Additionally, in vitro nodules are characterized by activated smooth muscle α-actin positive AVICs and high levels of apoptosis [2–3]. Mechanical strain has also been shown to influence nodule formation in excised AV leaflets [4]. Intracellular Ca2+ exhibits mechanodependency in cultured cells [5], and heightened levels of intracellular Ca2+ have been shown to be associated with apoptosis in many cell types [6] In this study, we assess the role of mechanically-induced changes in intracellular calcium and its function in modulating AVIC behavior. We hypothesized that intracellular Ca2+ will increase in strained AVICs and that over time, this will lead to apoptosis. We believe that the results from this study will help illustrate the mechanotransductive role of Ca2+ in AVICs and may elucidate early cellular changes that lead to AV calcification.

Calcific Nodule Morphogenesis by Aortic Valve Interstitial Cells: Synergism of Applied Strain and TGF-β1

2011 ◽  
Author(s):  
Joseph Chen ◽  
Charles I. Fisher ◽  
M. K. Sewell-Loftin ◽  
W. David Merryman
Keyword(s):  
Aortic Valve ◽  
The United States ◽  
Interstitial Cells ◽  
Nodule Formation ◽  
Matrix Stiffness ◽  
Calcific Aortic Valve Disease ◽  
Valve Interstitial Cells ◽  
Compliant Substrates ◽  
Tgf Β1

Calcific Aortic Valve Disease (CAVD) is the third most common cause of cardiovascular disease, affecting nearly 5 million people in the United States alone. It is now the most common form of acquired valvular disease in industrialized countries and will likely affect more individuals in the coming years as the prevalence increases with life expectancy. It is known that the progression of CAVD is closely related to the behavior of aortic valve interstitial cells (AVICs); however the cellular mechanobiological mechanisms leading to dysfunction remain unclear. Generally, CAVD is characterized by the formation of calcified AVIC aggregates with an apoptotic core. These aggregates increase the leaflet stiffness and impede normal valve function. Multiple studies have investigated the effects of various biochemical cues on this process, such as transformation growth factor β1 (TGF-β1), on the regulation of nodule formation [1]. Additionally, Yip et al revealed that matrix stiffness controls nodule formation in vitro, with stiffer substrates promoting apoptotic nodule formation, while compliant substrates generated nodules containing cells with osteoblast markers [2]. This suggests that matrix stiffness is involved in the regulatory mechanisms of nodule formation and may initiate different types of nodule formation (i.e. osteogenic vs. dystrophic). In the current study, we examined the synergistic role of strain and TGF-β1 in the generation of calcified nodules AVICs.

Abstract 18216: Epigenetic Up-regulation of α-smooth Muscle Actin Expression and Cell Aggregation in Human Aortic Valve Interstitial Cells Promotes Calcific Nodule Formation

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Rui Song ◽  
David A. Fullerton ◽  
Lihua Ao ◽  
Kesen Zhao ◽  
Xianzhong Meng
Keyword(s):  
Smooth Muscle ◽  
Aortic Valve ◽  
Smooth Muscle Actin ◽  
Cell Aggregation ◽  
Interstitial Cells ◽  
Nodule Formation ◽  
Muscle Actin ◽  
Aortic Valves ◽  
Valve Interstitial Cells ◽  
Tgf Β1

Older people are at risk of calcific aortic valve disease. Aortic valve interstitial cells (AVICs) play an important role in nodular calcification in aortic valve leaflets. AVICs in human aortic valves consist of fibroblasts and myofibroblasts that express α-smooth muscle actin (α-SMA). We have observed that AVICs of diseased aortic valves have greater osteogenic activities. However, molecular mechanism underlying AVIC formation of calcification nodules is not well understood. We hypothesized that an epigenetic mechanism promotes AVIC calcification nodule formation through induction of α-SMA expression and cell aggregation. Methods and Results: MiRNA profiles in AVICs from normal and diseased human aortic valves were analyzed by miRNA array and real-time qPCR. Diseased AVICs displayed higher levels of miR-486. Immunoblotting and immunofluorescence staining revealed that diseased AVICs had higher levels of α-SMA and α-SMA fibers. Inhibition of miR-486 by lentiviral-delivered miR-486 antagomir in diseased AVICs suppressed α-SMA expression and cell aggregation, resulting in reduced calcification nodule formation. Conversely, lentiviral-delivered miR-486 mimic in normal AVICs induced α-SMA expression and cell aggregation, leading to exacerbated calcification nodule formation. Stimulation of normal AVICs with pro-osteogenic mediators TGF-β1 and BMP-2 up-regulated miR-486 levels. MiR-486 antagomir reduced α-SMA expression, cell aggregation and calcification nodule formation in cells exposed to TGF-β1 or BMP-2. Further, miR-486 mimic induced AKT phosphorylation. Inhibition of AKT decreased α-SMA expression and cell aggregation induced by miR-486 mimic in normal AVICs. Knockdown of α-SMA suppressed cell aggregation and calcification nodule formation. Conclusions: The pro-osteogenic phenotype of AVICs of diseased aortic valves is associated with up-regulated levels of miR-486 and α-SMA. MiR-486 modulates the AKT pathway to up-regulate α-SMA expression and cell aggregation that are required for calcification nodule formation. These novel findings indicate that miR-486 contributes to the mechanism underlying aortic valve calcification and appears to be a therapeutic target for suppression of valvular osteogenic activity.

Cadherin-11 Regulates Calcific Nodule Formation by Aortic Valve Interstitial Cells

2013 ◽  
Author(s):  
Joseph Chen ◽  
Joshua D. Hutcheson ◽  
M. K. Sewell-Loftin ◽  
Larisa M. Ryzhova ◽  
Charles I. Fisher ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Transforming Growth Factor ◽  
Critical Role ◽  
Transforming Growth Factor Β1 ◽  
Interstitial Cells ◽  
In Vitro Models ◽  
Nodule Formation ◽  
Calcific Aortic Valve Disease ◽  
Valve Interstitial Cells

Calcific aortic valve disease (CAVD) is characterized by the stiffening and calcification of the aortic valve leaflets which result in impaired valve function and increased load on the myocardium. In vitro models of CAVD involve the formation the calcific nodules via aortic valve interstitial cells (AVICs). Transforming growth factor β1 (TGF-β1) induced myofibroblast differentiation of AVICs, which is evidenced by increased αSMA expression, has been shown to be a key mediator of dystrophic calcific nodule formation. Benton et al. demonstrated the critical role of αSMA in nodule formation in that when αSMA was suppressed, calcific nodules did not form [1]. Confoundingly, preventing phosphorylation of Erk1/2 with a MEK1/2 inhibitor leads to increased αSMA expression yet prevents calcific nodule formation [2], suggesting the requirement of another essential component of nodule formation that has yet to be revealed.

scholarly journals KPT-330 Prevents Aortic Valve Calcification via a Novel C/EBPβ Signaling Pathway

2021 ◽  
Vol 128 (9) ◽  
pp. 1300-1316
Author(s):  
Punashi Dutta ◽  
Karthik M. Kodigepalli ◽  
Stephanie LaHaye ◽  
J. Will Thompson ◽  
Sarah Rains ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Nuclear Export ◽  
The United States ◽  
Interstitial Cells ◽  
Nodule Formation ◽  
Calcific Aortic Valve Disease ◽  
Valve Interstitial Cells ◽  
Subsequent Decrease ◽  
Inhibitor Drug

Rationale: Calcific aortic valve disease (CAVD) affects >5.2 million people in the United States. The only effective treatment is surgery, and this comes with complications and no guarantee of long-term success. Objective: Outcomes from pharmacological initiatives remain unsubstantiated and, therefore, the aim of this study is to determine if repurposing a selective XPO1 (exportin-1) inhibitor drug (KPT-330) is beneficial in the treatment of CAVD. Methods and Results: We show that KPT-330 prevents, attenuates, and mitigates calcific nodule formation in heart valve interstitial cells in vitro and prevents CAVD in Klotho −/− mice. Using RNA-sequencing and mass spectrometry, we show that KPT-330’s beneficial effect is mediated by inhibiting nuclear export of the C/EBPβ (transcription factor CCAAT/enhancing-binding protein) in valve interstitial cells, leading to repression of canonical Wnt signaling, in part, through activation of the Wnt antagonist Axin1 , and a subsequent decrease in proosteogenic markers and cell viability. Conclusions: Our findings have met a critical need to discover alternative, pharmacological-based therapies in the treatment of CAVD.

scholarly journals Cardiac fibroblast mechanoresponse guides anisotropic organization of hiPSC-derived cardiomyocytes in vitro

2021 ◽  
Author(s):  
Dylan Mostert ◽  
Leda Klouda ◽  
Mark C. van Turnhout ◽  
Nicholas A. Kurniawan ◽  
Carlijn V.C Bouten
Keyword(s):  
Cardiac Fibroblasts ◽  
Mechanical Strain ◽  
Cardiac Injury ◽  
Cyclic Strain ◽  
Cell Types ◽  
Tissue Organization ◽  
A Cell ◽  
Human Cardiac Fibroblasts ◽  
And Function

ABSTRACTThe human myocardium is a mechanically active tissue typified by the anisotropic organization of cells and extracellular matrix (ECM). Upon injury, the composition of the myocardium changes, resulting in disruption of tissue organization and loss of coordinated contraction. Understanding how anisotropic organization in the adult myocardium is shaped and disrupted by environmental cues is thus critical, not only for unravelling the processes taking place during disease progression, but also for developing regenerative strategies to recover tissue function. Here, we decoupled in vitro the two major physical cues that are inherent in the myocardium: structural ECM and mechanical strain. We show that patterned ECM proteins control the orientation of the two main cell types in the myocardium: human cardiac fibroblasts (cFBs) and cardiomyocytes (hiPSC-CMs), despite their different mechanosensing machinery. Uniaxial cyclic strain, mimicking the local anisotropic deformation of the myocardium, did not affect hiPSC-CMs orientation. It did however induce a reorientation of cFBs, perpendicular to the strain direction, albeit this strain-avoidance response was overruled in the presence of anisotropic structural cues. These findings reveal that the mechanoresponsiveness of cFBs may be a critical handle in controlling myocardial tissue structure and function. To test this, we co-cultured hiPSC-CMs and cFBs in varying cell ratios to reconstruct normal and pathological myocardium. Contrary to the hiPSC-CM monoculture, the co-cultures adopted an anisotropic organization under uniaxial cyclic strain, regardless of the cell ratio. Together, these results identify the cFBs as a therapeutic target to mechanically restore structural organization of the tissue in cardiac regenerative therapies.SIGNIFICANCE STATEMENTUpon cardiac injury, adverse remodeling commonly leads to loss of the anisotropy that is typically found in human adult myocardium. Understanding the role of biophysical cues in shaping and disrupting the anisotropic tissue organization is essential to aid in the progress of cardiac regenerative strategies. Here, we report that the mechanoresponsiveness of cardiomyocytes (hiPSC-CMs) and cardiac fibroblasts (cFBs) differs significantly, resulting in a strain-induced reorganization response for cFBs but not for hiPSC-CMs. In co-culture with varying cell ratios of cFBs and hiPSC-CMs, the co-cultures adopted an anisotropic organization upon cyclic strain administration. Thus, our study proposes the mechanoresponse of cFBs, a cell type often overlooked in cardiac regenerative strategies, as a handle to restore myocardial architecture and function.

scholarly journals Activation of transmembrane receptor tyrosine kinase DDR1-STAT3 cascade by extracellular matrix remodeling promotes liver metastatic colonization in uveal melanoma

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Wei Dai ◽  
Shenglan Liu ◽  
Shubo Wang ◽  
Li Zhao ◽  
Xiao Yang ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cancer Cells ◽  
Uveal Melanoma ◽  
Specific Inhibitor ◽  
Type I ◽  
Matrix Remodeling ◽  
Metastatic Colonization ◽  
Tgf Β1

AbstractColonization is believed a rate-limiting step of metastasis cascade. However, its underlying mechanism is not well understood. Uveal melanoma (UM), which is featured with single organ liver metastasis, may provide a simplified model for realizing the complicated colonization process. Because DDR1 was identified to be overexpressed in UM cell lines and specimens, and abundant pathological deposition of extracellular matrix collagen, a type of DDR1 ligand, was noted in the microenvironment of liver in metastatic patients with UM, we postulated the hypothesis that DDR1 and its ligand might ignite the interaction between UM cells and their surrounding niche of liver thereby conferring strengthened survival, proliferation, stemness and eventually promoting metastatic colonization in liver. We tested this hypothesis and found that DDR1 promoted these malignant cellular phenotypes and facilitated metastatic colonization of UM in liver. Mechanistically, UM cells secreted TGF-β1 which induced quiescent hepatic stellate cells (qHSCs) into activated HSCs (aHSCs) which secreted collagen type I. Such a remodeling of extracellular matrix, in turn, activated DDR1, strengthening survival through upregulating STAT3-dependent Mcl-1 expression, enhancing stemness via upregulating STAT3-dependent SOX2, and promoting clonogenicity in cancer cells. Targeting DDR1 by using 7rh, a specific inhibitor, repressed proliferation and survival in vitro and in vivo outgrowth. More importantly, targeting cancer cells by pharmacological inactivation of DDR1 or targeting microenvironmental TGF-β1-collagen I loop exhibited a prominent anti-metastasis effect in mice. In conclusion, targeting DDR1 signaling and TGF-β signaling may be a novel approach to diminish hepatic metastasis in UM.

scholarly journals Computational Analysis of Fluid Flow Within a Device for Applying Biaxial Strain to Cultured Cells

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Jason Lee ◽  
Aaron B. Baker
Keyword(s):  
Shear Stress ◽  
Cultured Cells ◽  
Fluid Velocity ◽  
Mechanical Strain ◽  
Cell Types ◽  
Linear Increase ◽  
Shear Stresses ◽  
Biaxial Strain ◽  
Maximal Strain

In vitro systems for applying mechanical strain to cultured cells are commonly used to investigate cellular mechanotransduction pathways in a variety of cell types. These systems often apply mechanical forces to a flexible membrane on which cells are cultured. A consequence of the motion of the membrane in these systems is the generation of flow and the unintended application of shear stress to the cells. We recently described a flexible system for applying mechanical strain to cultured cells, which uses a linear motor to drive a piston array to create biaxial strain within multiwell culture plates. To better understand the fluidic stresses generated by this system and other systems of this type, we created a computational fluid dynamics model to simulate the flow during the mechanical loading cycle. Alterations in the frequency or maximal strain magnitude led to a linear increase in the average fluid velocity within the well and a nonlinear increase in the shear stress at the culture surface over the ranges tested (0.5–2.0 Hz and 1–10% maximal strain). For all cases, the applied shear stresses were relatively low and on the order of millipascal with a dynamic waveform having a primary and secondary peak in the shear stress over a single mechanical strain cycle. These findings should be considered when interpreting experimental results using these devices, particularly in the case when the cell type used is sensitive to low magnitude, oscillatory shear stresses.

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