A TRP to Pathological Angiogenesis and Vascular Normalization.

Uncontrolled angiogenesis underlies various pathological conditions such as cancer, age-related macular degeneration (AMD), and proliferative diabetic retinopathy (PDR). Hence, targeting pathological angiogenesis has become a promising strategy for the treatment of cancer and neovascular ocular diseases. However, current pharmacological treatments that target VEGF signaling have met with limited success either due to acquiring resistance against anti-VEGF therapies with serious side effects including nephrotoxicity and cardiovascular-related adverse effects in cancer patients or retinal vasculitis and intraocular inflammation after intravitreal injection in patients with AMD or PDR.

Angiotensin II induces endothelial dysfunction and vascular remodeling by downregulating TRPV4 channels.

Angiotensin II (Ang II) is a potent vasoconstrictor of vascular smooth muscle cells (VSMC) and is implicated in hypertension, but it's role in the regulation of endothelial function is not well known. We and others have previously shown that mechanically activated ion channel, Transient Receptor Potential Vanilloid 4 (TRPV4) mediates flow- and/or receptor-dependent vasodilation via nitric oxide (NO) production in endothelial cells. Ang II was demonstrated to crosstalk with TRPV4 via angiotensin 1 receptor (AT1R) and β-arrestin signaling in epithelial and immortalized cells, however, the role of this crosstalk in endothelial cell function is not fully explored.

Studying Angiogenesis Using Matrigel In Vitro and In Vivo.

Angiogenesis plays a critical role in physiology and pathophysiology of the human body; hence, it is important to explore the methods to study angiogenesis under in vitro and in vivo settings. Here, we describe three different methods to assess angiogenesis using Matrigel: an in vitro two- or three-dimensional (2D/3D) tube formation or angiogenesis assay using endothelial cells with growth factor supplemented Matrigel, an ex vivo sprouting angiogenesis assay embedding aortic rings in the Matrigel, and finally, Matrigel plug assays wherein Matrigels are implanted into the flanks of mice to assess the recruitment of endothelial cells to form new blood vessels in vivo.

Prostaglandin E attenuates lung fibroblast differentiation via inactivation of yes-associated protein signaling.

Prostaglandin E (PGE ) has been implicated in counteracting fibroblast differentiation by TGFβ1 during pulmonary fibrosis. However, the precise mechanism is not well understood. We show here that PGE via EP R and EP R inhibits the expression of mechanosensory molecules Lysyl Oxidase Like 2 (LOXL2), myocardin-related transcription factor A (MRTF-A), ECM proteins, plasminogen activation inhibitor 1 (PAI-1), fibronectin (FN), α-smooth muscle actin (α-SMA), and redox sensor (nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4)) required for TGFβ1-mediated fibroblast differentiation.

Deletion of Endothelial TRPV4 Protects Heart From Pressure Overload-Induced Hypertrophy.

Background: Left ventricular hypertrophy is a bipolar response, starting as an adaptive response to the hemodynamic challenge, but over time develops maladaptive pathology partly due to microvascular rarefaction and impaired coronary angiogenesis. Despite the profound influence on cardiac function, the mechanotransduction mechanisms that regulate coronary angiogenesis, leading to heart failure, are not well known.

Methods: We subjected endothelial-specific knockout mice of mechanically activated ion channel, TRPV4 (transient receptor potential cation channel subfamily V member 4; TRPV4) to pressure overload via transverse aortic constriction and examined cardiac function, cardiomyocyte hypertrophy, cardiac fibrosis, and apoptosis.

Epigenetic histone modification by butyrate downregulates KIT and attenuates mast cell function.

Short-chain fatty acid butyrate is produced from the bacterial fermentation of indigestible fiber in the intestinal lumen, and it has been shown to attenuate lung inflammation in murine asthma models. Mast cells (MCs) are initiators of inflammatory response to allergens, and they play an important role in asthma. MC survival and proliferation is regulated by its growth factor stem cell factor (SCF), which acts through the receptor, KIT.

Protein Kinase C α and β compensate for each other to promote stem cell factor-mediated KIT phosphorylation, mast cell viability and proliferation.

Mast cells (MCs) develop from hematopoietic progenitors and differentiate into mature MCs that reside within connective or mucosal tissues. Though the number of MCs in tissues usually remains constant, inflammation and asthma disturb this homeostasis, leading to proliferation of MCs. Understanding the signaling events behind this proliferative response could lead to the development of novel strategies for better management of allergic diseases.

Tumor-Derived Extracellular Vesicles Induce Abnormal Angiogenesis TRPV4 Downregulation and Subsequent Activation of YAP and VEGFR2.

Tumor angiogenesis is initiated and maintained by the tumor microenvironment through secretion of autocrine and paracrine factors, including extracellular vesicles (EVs). Although tumor-derived EVs (t-EVs) have been implicated in tumor angiogenesis, growth and metastasis, most studies on t-EVs are focused on proangiogenic miRNAs and growth factors. We have recently demonstrated that conditioned media from human lung tumor cells (A549) downregulate TRPV4 channels and transform normal endothelial cells to a tumor endothelial cell-like phenotype and induce abnormal angiogenesis t-EVs.

Leukotriene D Upregulates Oxidized Low-Density Lipoprotein Receptor 1 and CD36 to Enhance Oxidized LDL Uptake and Phagocytosis in Macrophages Through Cysteinyl Leukotriene Receptor 1.

Endothelial permeability, leukocyte attachment, and unregulated oxidized LDL (oxLDL) uptake by macrophages leading to the formation of foam cells are all vital in the initiation and progression of atherosclerosis. During inflammation, several inflammatory mediators regulate this process through the expression of distinct oxLDL binding cell surface receptors on macrophages. We have previously shown that Leukotriene D (LTD) promotes endothelial dysfunction, increasing endothelial permeability and enhancing TNFα-mediated attachment of monocytes to endothelium, which hints at its possible role in atherosclerosis.

TRPV4 Mechanotransduction in Fibrosis.

Fibrosis is an irreversible, debilitating condition marked by the excessive production of extracellular matrix and tissue scarring that eventually results in organ failure and disease. Differentiation of fibroblasts to hypersecretory myofibroblasts is the key event in fibrosis. Although both soluble and mechanical factors are implicated in fibroblast differentiation, much of the focus is on TGF-β signaling, but to date, there are no specific drugs available for the treatment of fibrosis.

NIR-emitting styryl dyes with large Stokes' shifts for imaging application: From cellular plasma membrane, mitochondria to Zebrafish neuromast.

Near-infrared (NIR) emitting probes with very large Stokes' shifts play a crucial role in bioimaging applications, as the optical signals in this region exhibit high signal to background ratio and allow deeper tissue penetration. Herein we illustrate NIR-emitting probe with very large Stokes' shifts (Δλ ≈ 260 - 272 nm) by integrating the excited-state intramolecular proton transfer (ESIPT) unit 2-(2'-hydroxyphenyl)benzoxazole (HBO) into a pyridinium derived cyanine. The ESIPT not only enhances the Stokes' shifts but also improves the quantum efficiency of the probe (ф = 0.

Spatial survey of non-collagenous proteins in mineralizing and non-mineralizing vertebrate tissues .

Bone biomineralization is a complex process in which type I collagen and associated non-collagenous proteins (NCPs), including glycoproteins and proteoglycans, interact closely with inorganic calcium and phosphate ions to control the precipitation of nanosized, non-stoichiometric hydroxyapatite (HAP, idealized stoichiometry Ca(PO)(OH)) within the organic matrix of a tissue. The ability of certain vertebrate tissues to mineralize is critically related to several aspects of their function. The goal of this study was to identify specific NCPs in mineralizing and non-mineralizing tissues of two animal models, rat and turkey, and to determine whether some NCPs are unique to each type of tissue.

Endothelial TRPV4 channels prevent tumor growth and metastasis via modulation of tumor angiogenesis and vascular integrity.

Transient receptor potential vanilloid 4 (TRPV4) is a ubiquitously expressed polymodally activated ion channel. TRPV4 has been implicated in tumor progression; however, the cell-specific role of TRPV4 in tumor growth, angiogenesis, and metastasis is unknown. Here, we generated endothelial-specific TRPV4 knockout (TRPV4) mice by crossing TRPV4 mice with Tie2-Cre mice.

Transient receptor potential vanilloid 4 channel deletion regulates pathological but not developmental retinal angiogenesis.

Transient receptor potential vanilloid 4 (TRPV4) channels are mechanosensitive ion channels that regulate systemic endothelial cell (EC) functions such as vasodilation, permeability, and angiogenesis. TRPV4 is expressed in retinal ganglion cells, Müller glia, pigment epithelium, microvascular ECs, and modulates cell volume regulation, calcium homeostasis, and survival. TRPV4-mediated physiological or pathological retinal angiogenesis remains poorly understood.

The role of TRPV4 channels in ocular function and pathologies.

Transient potential receptor vanilloid 4 (TRPV4) is an ion channel responsible for sensing osmotic and mechanical signals, which in turn regulates calcium signaling across cell membranes. TRPV4 is widely expressed throughout the body, and plays an important role in normal physiological function, as well as different pathologies, however, its role in the eye is not well known. In the eye, TRPV4 is expressed in various tissues, such as the retina, corneal epithelium, ciliary body, and the lens.

Transient Receptor Potential Vanilloid channel regulates fibroblast differentiation and airway remodeling by modulating redox signals through NADPH Oxidase 4.

Asthma is characterized by pathological airway remodeling resulting from persistent myofibroblast activation. Although transforming growth factor beta 1 (TGFβ1), mechanical signals, and reactive oxygen species (ROS) are implicated in fibroblast differentiation, their integration is still elusive. We identified that Transient Receptor Potential Vanilloid 4 (TRPV4), a mechanosensitive ion channel mediates lung fibroblast (LF) differentiation and D.

TRPV4 deletion protects heart from myocardial infarction-induced adverse remodeling via modulation of cardiac fibroblast differentiation.

Cardiac fibrosis caused by adverse cardiac remodeling following myocardial infarction can eventually lead to heart failure. Although the role of soluble factors such as TGF-β is well studied in cardiac fibrosis following myocardial injury, the physiological role of mechanotransduction is not fully understood. Here, we investigated the molecular mechanism and functional role of TRPV4 mechanotransduction in cardiac fibrosis.

Extracellular Vesicles From Pathological Microenvironment Induce Endothelial Cell Transformation and Abnormal Angiogenesis via Modulation of TRPV4 Channels.

The soluble and mechanical microenvironment surrounding endothelial cells influences and instructs them to form new blood vessels. The cells in the pathological tumor microenvironment release extracellular vesicles (EVs) for paracrine signaling. EVs have been shown to induce angiogenesis by communicating with endothelial cells, but the underlying molecular mechanisms are not well known.

A NIR-emitting cyanine with large Stokes shifts for live cell imaging: large impact of the phenol group on emission.

There are a limited number of near-infrared (NIR) emitting (λem = 700-900 nm) molecular probes for imaging applications. A NIR-emitting probe that exhibits emission at ∼800 nm with a large Stokes shift was synthesized and found to exhibit excellent selectivity towards mitochondria for live-cell imaging. The photophysical properties were attributed to an excited "cyanine structure" via intramolecular charge transfer (ICT) involving a phenol group.

NIR-Emitting Hemicyanines with Large Stokes' Shifts for Live Cell Imaging: from Lysosome to Mitochondria Selectivity by Substituent Effect.

Lysosome imaging without perturbing intracellular activity remains challenging, as the current commercial lysosome probes contain weakly basic amino groups that could perturb lysosome pH. Herein, we illustrate NIR-emitting dyes 2 and 3 (λ ≈ 700 nm) with very large Stokes' shifts (Δλ = 231-246 nm), attributing to the presence of a 2-hydroxyphenyl(benzo[d]oxazol) (HBO) unit that undergoes excited-state intramolecular proton transfer (ESIPT). The structures of and also contain a hemicyanine unit with benzothiazolium and indolium as a terminal group, respectively.

Cysteinyl leukotriene 2 receptor promotes endothelial permeability, tumor angiogenesis, and metastasis.

Cysteinyl leukotrienes (cys-LTs) are proinflammatory mediators that enhance vascular permeability through distinct receptors (CysLTRs). We found that CysLTR regulates angiogenesis in isolated mouse endothelial cells (ECs) and in Matrigel implants in WT mice and enhances EC contraction and permeability via the Rho-dependent myosin light chain 2 and vascular endothelial (VE)-cadherin axis. Since solid tumors utilize aberrant angiogenesis for their growth and metastasis and their vessels exhibit vascular hyperpermeability, we hypothesized that CysLTR, via its actions on the endothelium, might regulate tumor growth.

Mechanosensitive TRPV4 channels stabilize VE-cadherin junctions to regulate tumor vascular integrity and metastasis.

The transient receptor potential vanilloid 4 (TRPV4) channel is a mechanosensor in endothelial cells (EC) that regulates cyclic strain-induced reorientation and flow-mediated nitric oxide production. We have recently demonstrated that TRPV4 expression is reduced in tumor EC and tumors grown in TRPV4KO mice exhibited enhanced growth and immature leaky vessels. However, the mechanism by which TRPV4 regulates tumor vascular integrity and metastasis is not known.

Novel noncanonical regulation of soluble VEGF/VEGFR2 signaling by mechanosensitive ion channel TRPV4.

VEGF signaling via VEGF receptor-2 (VEGFR2) is a major regulator of endothelial cell (EC) functions, including angiogenesis. Although most studies of angiogenesis focus on soluble VEGF signaling, mechanical signaling also plays a critical role. Here, we examined the consequence of disruption of mechanical signaling on soluble signaling pathways.