An NIR-emitting probe (λ_em ∼ 700 nm) with a large Stokes shift (Δλ ≈ 234 nm) is synthesized by using excited-state intramolecular proton transfer (ESIPT). The phenolic proton, which controls ESIPT, acts as a switch to give strong fluorescence at pH ≈ 5. The probe can selectively show lysosome organelles, therefore leading to a lysosome probe without exhibiting “an alkalinizing effect”.

Cysteinyl leukotrienes (cys-LTs), LTC₄, LTD₄, LTE₄ are potent inflammatory lipid mediators that act through two distinct G-protein-coupled receptors, CysLT₁R and CysLT₂R. Although cys-LTs are shown to induce vascular leakage and atherosclerosis, the molecular mechanism by which cys-LTs modulate endothelial function is not known. Here, we show that cys-LTs (LTC₄ and LTD₄) induce robust calcium influx in human umbilical vein endothelial cells (HUVECs) through CysLT₂R, but not CysLT₁R. Further, cys-LT treatment induced endothelial cell (EC) contraction leading to monolayer disruption via CysLT₂R/Rho kinase dependent pathway. Furthermore, stimulation with cys-LTs potentiated TNFα-induced VCAM-1 expression and leukocyte recruitment to ECs through CysLT₂R. In contrast, we found that both LTC₄ and LTD₄ stimulated EC proliferation through CysLT₁R. Taken together, these results suggest that cys-LTs induce endothelial inflammation and proliferation via CysLT₂R/Rho kinase and CysLT₁R/Erk dependent pathways, respectively, which play critical role in the etiology of cardiovascular diseases such as atherosclerosis and myocardial infarction.

Virtual “online” teaching has been adopted by most universities around the world during the COVID-19 outbreak. This study aims to investigate the factors that might affect students’ preference for virtual learning. Since a second wave of such pandemic is expected to occur, professors and teaching assistants may want to be prepared and aware to create an effective virtual learning environment for students.

Contributions of mechanical signals to airway remodeling during asthma are poorly understood. Transient receptor potential vanilloid 4 (TRPV4), a mechanosensitive ion channel, has been implicated in cardiac and pulmonary fibrosis; however, its role in asthma remains elusive. Employing a Dermatophagoides farinae– induced asthma model, we report here that TRPV4‐knockout mice were protected from D. farinae– induced airway remodeling. Furthermore, lung fibroblasts that were isolated from TRPV4‐knockout mice showed diminished differentiation potential compared with wild‐type mice. Fibroblasts from asthmatic lung exhibited increased TRPV4 activity and enhanced differentiation potential compared with normal human lung fibroblasts. Of interest, TGF‐β1 treatment enhanced TRPV4 activation in a PI3K‐dependent manner in normal human lung fibroblasts in vitro . Mechanistically, TRPV4 modulated matrix remodeling in the lung via 2 distinct but dependent pathways: one enhances matrix deposition by fibrotic gene activation, whereas the other slows down matrix degradation by increased plasminogen activator inhibitor 1. Of importance, both pathways are regulated by Rho/myocardin‐related transcription factor‐A and contribute to fibroblast differentiation and matrix remodeling in the lung. Thus, our results support a unique role for TRPV4 in D. farinae– induced airway remodeling and warrant further studies in humans for it to be used as a novel therapeutic target in the treatment of asthma. —Gombedza, F., Kondeti, V., Al‐Azzam, N., Koppes, S., Duah, E., Patil, P., Hexter, M., Phillips, D., Thodeti, C. K., Paruchuri, S. Mechanosensitive transient receptor potential vanilloid 4 regulates Dermatophagoides farinae– induced airway remodeling via 2 distinct pathways modulating matrix synthesis and degradation. FASEB J . 31, 1556–1570 (2017) www.fasebj.org

Calcium crystal internalization into proximal tubular (PT) cells results in acute kidney injury, nephrocalcinosis, chronic kidney disease (CKD), and kidney-stone formation. Ca²⁺ supersaturation in PT luminal fluid induces calcium crystal formation, leading to aberrant crystal internalization into PT cells. While such crystal internalization produces reactive oxygen species (ROS), cell membrane damage, and apoptosis; the upstream signaling events involving dysregulation of intracellular Ca²⁺ homeostasis and ER stress, remain largely unknown. We have recently described a transepithelial Ca²⁺ transport pathway regulated by receptor-operated Ca²⁺ entry (ROCE) in PT cells. Therefore, we examined the pathophysiological consequence of internalization of stone-forming calcium crystals such as calcium phosphate (CaP), calcium oxalate (CaOx), and CaP + CaOx (mixed) crystals on the regulation of intracellular Ca²⁺ signaling by measuring dynamic changes in Ca²⁺ transients in HK2, human PT cells, using pharmacological and siRNA inhibitors. The subsequent effect on ER stress was measured by changes in ER morphology, ER stress-related gene expression, endogenous ROS production, apoptosis, and necrosis. Interestingly, our data show that crystal internalization induced G-protein-coupled receptor-mediated sustained rise in intracellular Ca²⁺ concentration ([Ca²⁺]_i) via store-operated Ca²⁺ entry (SOCE); suggesting that the mode of Ca²⁺ entry switches from ROCE to SOCE following crystal internalization. We found that SOCE components—stromal interacting molecules 1 and 2 (STIM1, STIM2) and ORAI3 (SOCE) channel were upregulated in these crystal-internalized cells, which induced ER stress, ROS production, and cell death. Finally, silencing those SOCE genes protected crystal-internalized cells from prolonged [Ca²⁺]_i rise and ER stress. Our data provide insight into the molecular mechanism of crystal-induced Ca²⁺ dysregulation, ER stress, and PT cell death and thus could have a translational role in treating crystal nephropathies including kidney stones. Taken together, modulation of Ca²⁺ signaling can be used as a tool to reverse the pathological consequence of crystal-induced conditions including cardiovascular calcification.