Cell senescence is a key process in age-associated dysfunction and diseases, notably chronic obstructive pulmonary disease (COPD). We previously identified phospholipase A2-receptor 1 (PLA2R1) as a positive regulator of cell senescence acting JAK/STAT signalling. Its role in pathology, however, remains unknown. Here, we assessed PLA2R1-induced senescence in COPD and lung emphysema pathogenesis. Assessment of cell senescence in lungs and cultured lung cells from patients with COPD and controls subjected to PLA2R1 knock-down, gene transduction and treatment with the JAK1/2 inhibitor ruxolitinib. To assess whether upregulation caused lung lesions, we developed transgenic mice overexpressing ( -TG) and intratracheally injected wild-type mice with a lentiviral vector carrying the gene (LV- mice). We found that was overexpressed in various cell types exhibiting senescence characteristics in COPD lungs. knockdown extended the population doubling capacity of these cells and inhibited their proinflammatory senescence-associated secretory phenotype (SASP). PLA2R1-mediated cell senescence in COPD was largely reversed by treatment with the potent JAK1/2 inhibitor ruxolitinib. 5 month-old -TG mice exhibited lung-cell senescence and developed lung emphysema and lung fibrosis together with pulmonary hypertension. Treatment with ruxolitinib induced reversal of lung emphysema and fibrosis. LV- -treated mice developed lung emphysema within 4 weeks, and this was markedly attenuated by concomitant ruxolitinib treatment. Our data support a major role for PLA2R1 activation in driving lung-cell senescence and lung alterations in COPD. Targeting JAK1/2 may represent a promising therapeutic approach for COPD. Our data support a major role for PLA2R1 activation in driving lung-cell senescence and lung alterations in COPD. Targeting JAK1/2 may represent a promising therapeutic approach for COPD.Infantile myofibromatosis (IMF) is a benign tumor form characterized by the development of nonmetastatic tumors in skin, bone, muscle and sometimes viscera. Autosomal dominant forms of IMF are caused by mutations in the PDGFRB gene, but a family carrying a L1519P mutation in the NOTCH3 gene has also recently been identified. In this report, we address the molecular consequences of the NOTCH3L1519P mutation and the relationship between the NOTCH and PDGFRB signaling in IMF. The NOTCH3L1519P receptor generates enhanced downstream signaling in a ligand-independent manner. Despite the enhanced signaling, the NOTCH3L1519P receptor is absent from the cell surface and instead accumulates in the endoplasmic reticulum. Furthermore, the localization of the NOTCH3L1519P receptor in the bipartite, heterodimeric state is altered, combined with avid secretion of the mutated extracellular domain from the cell. Chloroquine treatment strongly reduces the amount of secreted NOTCH3L1519P extracellular domain and decreases signaling. Finally, NOTCH3L1519P upregulates PDGFRB expression in fibroblasts, supporting a functional link between Notch and PDGF dysregulation in IMF. Collectively, our data define a NOTCH3-PDGFRB axis in IMF, where an IMF-mutated NOTCH3 receptor elevates PDGFRB expression. The functional characterization of a ligand-independent gain-of-function NOTCH3 mutation is important for Notch therapy considerations for IMF, including strategies aimed at altering lysosome function.The detection of temporal variations in amplitude of light intensity, or temporal contrast sensitivity (TCS), depends on the kinetics of rod photoresponse recovery. Uncharacteristically fast rod recovery kinetics are facets of both human patients and transgenic animal models with a P23H rhodopsin mutation, a prevalent cause of retinitis pigmentosa (RP). Here, we show that mice with this mutation (RhoP23H/+) exhibit an age-dependent and illumination-dependent enhancement in TCS compared with controls. At retinal illumination levels producing ≥1000 R*/rod/s or more, postnatal day 30 (P30) RhoP23H/+ mice exhibit a 1.2-fold to 2-fold increase in retinal and optomotor TCS relative to controls in response to flicker frequencies of 3, 6, and 12 Hz despite significant photoreceptor degeneration and loss of flash electroretinogram (ERG) b-wave amplitude. Surprisingly, the TCS of RhoP23H/+ mice further increases as degeneration advances. Enhanced TCS is also observed in a second model (rhodopsin heterozygous mice, Rho+/-) with fast rod recovery kinetics and no apparent retinal degeneration. In both mouse models, enhanced TCS is explained quantitatively by a comprehensive model that includes photoresponse recovery kinetics, density and collecting area of degenerating rods. https://www.selleckchem.com/products/qx77.html Measurement of TCS may be a non-invasive early diagnostic tool indicative of rod dysfunction in some forms of retinal degenerative disease.The mechanotransduction (MT) complex in auditory hair cells converts the mechanical stimulation of sound waves into neural signals. Recently, the MT complex has been suggested to contain at least four distinct integral membrane proteins protocadherin 15 (PCDH15), transmembrane channel-like protein 1 (TMC1), lipoma HMGIC fusion partner-like 5 (LHFPL5), and transmembrane inner ear protein (TMIE). However, the composition, function, and regulation of the MT-complex proteins remain incompletely investigated. Here, we report previously undescribed splicing isoforms of TMC1, LHFPL5, and TMIE. We identified four alternative splicing events for the genes encoding these three proteins by analyzing RNA-seq libraries of auditory hair cells from adult mice [over postnatal day (P)28], and we then verified the alternative splicing events by using RT-PCR and Sanger sequencing. Moreover, we examined the tissue-specific distribution, developmental expression patterns, and tonotopic gradient of the splicing isoforms by performing semiquantitative and quantitative real-time PCR (qRT-PCR), and we found that the alternative splicing of TMC1 and LHFPL5 is cochlear-specific and occurs in both neonatal and adult mouse cochleae. Our findings not only reveal the potential complexity of the MT-complex composition, but also provide critical insights for guiding future research on the function, regulation, and trafficking of TMC1, LHFPL5, and TMIE and on the clinical diagnosis of hearing loss related to aberrant splicing of these three key genes in hearing.