Photokeratitis in Outdoor Event Participants Exposed to UV Radiation Display.

Importance: While UV radiation displays may be used for recreational purposes at outdoor events, unprotected eyes have been reported to have symptoms consistent with photokeratitis. Such symptoms warrant documentation and evaluation in ophthalmic peer reviewed literature. Objective: To describe a case series of photokeratitis associated with a single ultraviolet radiation display at an outdoor event. Design, Setting, and Participants: This case series involved a retrospective record review of 8 patients who presented in public and private health sectors in November 2023 after developing photokeratitis following UV radiation exposure at an outdoor event in Hong Kong on the night of November 4, 2023. Main Outcomes and Measures: Clinical symptoms, signs, and clinical course of patients who were diagnosed acute photokeratitis following exposure to UV radiation. Results: The mean time of UV display exposure for the 8 patients (mean [SD] age, 33.12 [5.19] years; 4 [50%] female) was 3.00 (1.41) hours, and symptoms presented at a mean (SD) 8.88 (8.24) hours after the exposure. None of the patients were wearing spectacles during the exposed period. All patients were affected bilaterally. All patients experienced eye pain, 6 experienced red eye, and 5 experienced tearing and photophobia. Mean (SD) presenting visual acuity was logMAR 0.10 (0.14) (approximate Snellen equivalent, 20/25) for right eyes and 0.06 (0.89) (approximate Snellen equivalent, 20/25) for left eyes. On examination, there were findings of cornea and conjunctival involvement with punctate epithelial erosions and ciliary vasodilation, but none of the patients presented with anterior chamber reaction. Corticosteroids, lubricants, and antibiotics, all provided topically, were prescribed. Five patients were not scheduled for a review, and 3 had follow-up visits, with the length of follow-up ranging from 7 to 10 days. All patients had undergone a complete recovery. Conclusions and Relevance: These findings provide evidence of an association between UV radiation used for recreational purposes and photokeratitis, which may help guide evaluation and management of future cases.

Pulmonary Hypertension Induces Serotonin Hyperreactivity and Metabolic Reprogramming in Coronary Arteries via NOX1/4-TRPM2 Signaling Pathway.

BACKGROUND: Clinical evidence revealed abnormal prevalence of coronary artery (CA) disease in patients with pulmonary hypertension (PH). The mechanistic connection between PH and CA disease is unclear. Serotonin (5-hydroxytryptamine), reactive oxygen species, and Ca2+ signaling have been implicated in both PH and CA disease. Our recent study indicates that NOXs (NADPH [nicotinamide adenine dinucleotide phosphate] oxidases) and TRPM2 (transient receptor potential cation channel subfamily M member 2) are key components of their interplay. We hypothesize that activation of the NOX-TRPM2 pathway facilitates the remodeling of CA in PH. METHODS: Left and right CAs from chronic hypoxia and monocrotaline-induced PH rats were collected to study vascular reactivity, gene expression, metabolism, and mitochondrial function. Inhibitors or specific siRNA were used to examine the pathological functions of NOX1/4-TRPM2 in CA smooth muscle cells. RESULTS: Significant CA remodeling and 5-hydroxytryptamine hyperreactivity in the right CA were observed in PH rats. NOX1/4-mediated reactive oxygen species production coupled with TRPM2-mediated Ca2+ influx contributed to 5-hydroxytryptamine hyperresponsiveness. CA smooth muscle cells from chronic hypoxia-PH rats exhibited increased proliferation, migration, apoptosis, and metabolic reprogramming in an NOX1/4-TRPM2-dependent manner. Furthermore, the NOX1/4-TRPM2 pathway participated in mitochondrial dysfunction, involving mitochondrial DNA damage, reactive oxygen species production, elevated mitochondrial membrane potential, mitochondrial Ca2+ accumulation, and mitochondrial fission. In vivo knockdown of NOX1/4 alleviated PH and suppressed CA remodeling in chronic hypoxia rats. CONCLUSIONS: PH triggers an increase in 5-hydroxytryptamine reactivity in the right CA and provokes metabolic reprogramming and mitochondrial disruption in CA smooth muscle cells via NOX1/4-TRPM2 activation. This signaling pathway may play an important role in CA remodeling and CA disease in PH.

Carotid body denervation improves hyperglycemia in obese mice.

The carotid bodies (CBs) have been implicated in glucose abnormalities in obesity via elevation of activity of the sympathetic nervous system. Obesity-induced hypertension is mediated by insulin receptor (INSR) signaling and by leptin, which binds to the leptin receptor (LEPRb) in CB and activates transient receptor potential channel subfamily M member 7 (TRPM7). We hypothesize that in mice with diet-induced obesity, hyperglycemia, glucose intolerance, and insulin resistance will be attenuated by the CB denervation (carotid sinus nerve dissection, CSND) and by knockdown of Leprb, Trpm7, and Insr gene expression in CB. In series of experiments in 75 male diet-induced obese (DIO) mice, we performed either CSND (vs. sham) surgeries or shRNA-induced suppression of Leprb, Trpm7, or Insr gene expression in CB, followed by blood pressure telemetry, intraperitoneal glucose tolerance and insulin tolerance tests, and measurements of fasting plasma insulin, leptin, corticosterone, glucagon and free fatty acids (FFAs) levels, hepatic expression of gluconeogenesis enzymes phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G-6-Pase) mRNA and liver glycogen levels. CSND decreased blood pressure, fasting blood glucose levels and improved glucose tolerance without any effect on insulin resistance. CSND did not affect any hormone levels and gluconeogenesis enzymes, but increased liver glycogen level. Genetic knockdown of CB Leprb, Trpm7, and Insr had no effect on glucose metabolism. We conclude that CB contributes to hyperglycemia of obesity, probably by modulation of the glycogen-glucose equilibrium. Diabetogenic effects of obesity on CB in mice do not occur via activation of CB Leprb, Trpm7, and Insr.NEW & NOTEWORTHY This paper provides first evidence that carotid body denervation abolishes hypertension and improves fasting blood glucose levels and glucose tolerance in mice with diet-induced obesity. Furthermore, we have shown that this phenomenon is associated with increased liver glycogen content, whereas insulin sensitivity and enzymes of gluconeogenesis were not affected.

Epac induces ryanodine receptor-dependent intracellular and inter-organellar calcium mobilization in mpkCCD cells.

Arginine vasopressin (AVP) induces an increase in intracellular Ca2+ concentration ([Ca2+]i) with an oscillatory pattern in isolated perfused kidney inner medullary collecting duct (IMCD). The AVP-induced Ca2+ mobilization in inner medullary collecting ducts is essential for apical exocytosis and is mediated by the exchange protein directly activated by cyclic adenosine monophosphate (Epac). Murine principal kidney cortical collecting duct cells (mpkCCD) is the cell model used for transcriptomic and phosphoproteomic studies of AVP signaling in kidney collecting duct. The present study examined the characteristics of Ca2+ mobilization in mpkCCD cells, and utilized mpkCCD as a model to investigate the Epac-induced intracellular and intra-organellar Ca2+ mobilization. Ca2+ mobilization in cytosol, endoplasmic reticulum lumen, and mitochondrial matrix were monitored with a Ca2+ sensitive fluorescent probe and site-specific Ca2+ sensitive biosensors. Fluorescence images of mpkCCD cells and isolated perfused inner medullary duct were collected with confocal microscopy. Cell permeant ligands of ryanodine receptors (RyRs) and inositol 1,4,5 trisphosphate receptors (IP3Rs) both triggered increase of [Ca2+]i and Ca2+ oscillations in mpkCCD cells as reported previously in IMCD. The cell permeant Epac-specific cAMP analog Me-cAMP/AM also caused a robust Ca2+ mobilization and oscillations in mpkCCD cells. Using biosensors to monitor endoplasmic reticulum (ER) luminal Ca2+ and mitochondrial matrix Ca2+, Me-cAMP/AM not only triggered Ca2+ release from ER into cytoplasm, but also shuttled Ca2+ from ER into mitochondria. The Epac-agonist induced synchronized Ca2+ spikes in cytosol and mitochondrial matrix, with concomitant declines in ER luminal Ca2+. Me-cAMP/AM also effectively triggered store-operated Ca2+ entry (SOCE), suggesting that Epac-agonist is capable of depleting ER Ca2+ stores. These Epac-induced intracellular and inter-organelle Ca2+ signals were mimicked by the RyR agonist 4-CMC, but they were distinctly different from IP3R activation. The present study hence demonstrated that mpkCCD cells retain all reported features of Ca2+ mobilization observed in isolated perfused IMCD. It further revealed information on the dynamics of Epac-induced RyR-dependent Ca2+ signaling and ER-mitochondrial Ca2+ transfer. ER-mitochondrial Ca2+ coupling may play a key role in the regulation of ATP and reactive oxygen species (ROS) production in the mitochondria along the nephron. Our data suggest that mpkCCD cells can serve as a renal cell model to address novel questions of how mitochondrial Ca2+ regulates cytosolic Ca2+ signals, inter-organellar Ca2+ signaling, and renal tubular functions.

TRPM7 channels regulate breathing during sleep in obesity by acting peripherally in the carotid bodies.

Sleep-disordered breathing (SDB) affects over 50% of obese individuals. Exaggerated hypoxic chemoreflex is a cardinal trait of SDB in obesity. We have shown that leptin acts in the carotid bodies (CB) to augment chemoreflex and that leptin activates the transient receptor potential melastatin 7 (TRPM7) channel. However, the effect of leptin-TRPM7 signalling in CB on breathing and SDB has not been characterized in diet-induced obesity (DIO). We hypothesized that leptin acts via TRPM7 in the CB to increase chemoreflex leading to SDB in obesity. DIO mice were implanted with EEG/EMG electrodes and transfected with Leprb short hairpin RNA (shRNA) or Trpm7 shRNA vs. control shRNA in the CB area bilaterally. Mice underwent a full-polysomnography and metabolic studies at baseline and after transfection. Ventilatory responses to hypoxia and hypercapnia were assessed during wakefulness. Leprb and Trpm7 were upregulated and their promoters were demethylated in the CB of DIO mice. Leprb knockdown in the CB did not significantly affect ventilation. Trpm7 knockdown in the CB stimulated breathing during sleep in normoxia. These effects were not driven by changes in CB chemosensitivity or metabolism. Under sustained hypoxia, Trpm7 shRNA in the CB augmented ventilation during sleep, but decreased oxyhaemoglobin saturation. We conclude that the suppression of TRPM7 in the CB improved sleep-related hypoventilation and that the respiratory effects of CB TRPM7 channels in obesity are independent of leptin. TRPM7 signalling in the CB could be a therapeutic target for the treatment of obesity-related SDB. KEY POINTS: The leptin-TRPM7 axis in the carotid bodies may play an important role in the pathogenesis of sleep-disordered breathing. TRPM7 channels regulate breathing during sleep by acting peripherally in the carotid bodies. Suppression of TRPM7 signalling in the carotid bodies improves the obesity-induced hypoventilation in mice. Pharmacological blockade of TRPM7 channels in the carotid bodies could be a therapy for sleep-disordered breathing in obesity.

Reduced CircSMOC1 Level Promotes Metabolic Reprogramming via PTBP1 (Polypyrimidine Tract-Binding Protein) and miR-329-3p in Pulmonary Arterial Hypertension Rats.

BACKGROUND: Pulmonary arterial hypertension maintains rapid cell proliferation and vascular remodeling through metabolic reprogramming. Recent studies suggested that circRNAs play important role in pulmonary vascular remodeling and pulmonary arterial smooth muscle cells proliferation. However, the relationship between circRNA, cell proliferation, and metabolic reprogramming in pulmonary arterial hypertension has not been investigated. METHODS: RNA-seq and qRT-PCR reveal the differential expression profile of circRNA in pulmonary arteries of pulmonary arterial hypertension rat models. Transfection was used to examine the effects of circSMOC1 on pulmonary artery smooth muscle cells, and the roles of circSMOC1 in vivo were investigated by adenoassociated virus. Mass spectrometry, RNA pull-down, RNA immunoprecipitation, and dual-luciferase reporter assay were performed to investigate the signaling pathway of circSMOC1 regulating the metabolic reprogramming. RESULTS: CircSMOC1 was significantly downregulated in pulmonary arteries of pulmonary arterial hypertension rats. CircSMOC1 knockdown promoted proliferation and migration and enhanced aerobic glycolysis of pulmonary artery smooth muscle cells. CircSMOC1 overexpression in vivo alleviates pulmonary vascular remodeling, right ventricular pressure, and right heart hypertrophy. In the nucleus, circSMOC1 directly binds to PTBP1 (polypyrimidine tract-binding protein), competitively inhibits the specific splicing of PKM (pyruvate kinase M) premRNA, resulting in the upregulation of PKM2 (pyruvate kinase M2), the key enzyme of aerobic glycolysis, to enhance glycolysis. In the cytoplasm, circSMOC1 acted as a miR-329-3p sponge, and its reduction in pulmonary arterial hypertension suppressed PDHB (pyruvate dehydrogenase E1 subunit beta) expression, leading to the impairment of mitochondrial oxidative phosphorylation. CONCLUSIONS: circSMOC1 is crucially involved in the metabolic reprogramming of pulmonary artery smooth muscle cells through PTBP1 and miR-329-3p to regulate pulmonary vascular remodeling in pulmonary arterial hypertension.

Ryanodine receptor 1-mediated Ca2+ signaling and mitochondrial reprogramming modulate uterine serous cancer malignant phenotypes.

BACKGROUND: Uterine serous cancer (USC) is the most common non-endometrioid subtype of uterine cancer, and is also the most aggressive. Most patients will die of progressively chemotherapy-resistant disease, and the development of new therapies that can target USC remains a major unmet clinical need. This study sought to determine the molecular mechanism by which a novel unfavorable prognostic biomarker ryanodine receptor 1 (RYR1) identified in advanced USC confers their malignant phenotypes, and demonstrated the efficacy of targeting RYR1 by repositioned FDA-approved compounds in USC treatment. METHODS: TCGA USC dataset was analyzed to identify top genes that are associated with patient survival or disease stage, and can be targeted by FDA-approved compounds. The top gene RYR1 was selected and the functional role of RYR1 in USC progression was determined by silencing and over-expressing RYR1 in USC cells in vitro and in vivo. The molecular mechanism and signaling networks associated with the functional role of RYR1 in USC progression were determined by reverse phase protein arrays (RPPA), Western blot, and transcriptomic profiling analyses. The efficacy of the repositioned compound dantrolene on USC progression was determined using both in vitro and in vivo models. RESULTS: High expression level of RYR1 in the tumors is associated with advanced stage of the disease. Inhibition of RYR1 suppressed proliferation, migration and enhanced apoptosis through Ca2+-dependent activation of AKT/CREB/PGC-1α and AKT/HK1/2 signaling pathways, which modulate mitochondrial bioenergetics properties, including oxidative phosphorylation, ATP production, mitochondrial membrane potential, ROS production and TCA metabolites, and glycolytic activities in USC cells. Repositioned compound dantrolene suppressed USC progression and survival in mouse models. CONCLUSIONS: These findings provided insight into the mechanism by which RYR1 modulates the malignant phenotypes of USC and could aid in the development of dantrolene as a repurposed therapeutic agent for the treatment of USC to improve patient survival.

TRPC3 promotes tumorigenesis of gastric cancer via the CNB2/GSK3ß/NFATc2 signaling pathway.

The transient receptor potential canonical (TRPC) channels have been implicated in various types of malignancies including gastric cancer (GC). However, the detailed mechanisms of TRPC channels underlying cell proliferation and apoptosis of GC cells remain largely unknown. Here, we report that TRPC3 was highly expressed in clinical GC specimens and correlated with GC malignant progression and poor prognosis. Forced expression of TRPC3 in GC cells enhanced both receptor-operated Ca2+ entry (ROCE) and store-operated Ca2+ entry (SOCE) and promoted the nuclear factor of activated T cell 2 (NFATc2) nuclear translocation by AKT/GSK-3ß and CNB2 signaling. Pharmacological inhibition of TRPC3 or CRISPR/Cas9-mediated TRPC3 knockout effectively inhibited the growth of GC cells both in vitro and in vivo. These effects were reversible by the rescue of TRPC3 expression. Furthermore, we confirmed the role of TRPC3 and the ROCE-AKT/GSK3ß-CNB2/NFATc2 signaling cascade in regulating cell cycle checkpoint, apoptosis cascade, and intracellular ROS production in GC. Overall, our findings suggest an oncogenic role of TRPC3 in GC and may highlight a potential target of TRPC3 for therapeutic intervention of GC and its malignant progression.

Increased intracellular Cl- concentration in pulmonary arterial myocytes is associated with chronic hypoxic pulmonary hypertension.

Chloride channels play an important role in regulating smooth muscle contraction and proliferation, and contribute to the enhanced constriction of pulmonary arteries (PAs) in pulmonary hypertension (PH). The intracellular Cl- concentration ([Cl-]i), tightly regulated by various Cl- transporters, determines the driving force for Cl- conductance, thereby the functional outcome of Cl- channel activation. This study characterizes for the first time the expression profile of Cl- transporters/exchangers in PA smooth muscle and provides the first evidence that the intracellular Cl- homeostasis is altered in PA smooth muscle cells (PASMCs) associated with chronic hypoxic PH (CHPH). Quantitative RT-PCR revealed that the endothelium-denuded intralobar PA of rats expressed Slc12a gene family-encoded Na-K-2Cl cotransporter 1 (NKCC1), K-Cl cotransporters (KCC) 1, 3, and 4, and Slc4a gene family-encoded Na+-independent and Na+-dependent Cl-/HCO3- exchangers. Exposure of rats to chronic hypoxia (10% O2, 3 wk) caused CHPH and selectively increased the expression of Cl--accumulating NKCC1 and reduced the Cl--extruding KCC4. The intracellular Cl- concentration ([Cl-]i) averaged at 45 mM and 47 mM in normoxic PASMCs as determined by fluorescent indicator MEQ and by gramicidin-perforated patch-clamp technique, respectively. The ([Cl-]i was increased by ∼10 mM in PASMCs of rats with CHPH. Future studies are warranted to further establish the hypothesis that the altered intracellular Cl- homeostasis contributes to the pathogenesis of CHPH.

Pharmacological and Genetic Blockade of Trpm7 in the Carotid Body Treats Obesity-Induced Hypertension.

[Figure: see text].

Leptin Induces Epigenetic Regulation of Transient Receptor Potential Melastatin 7 in Rat Adrenal Pheochromocytoma Cells.

Obesity elevates the plasma level of leptin, which has been associated with hypertension. Our recent studies in mice demonstrated that leptin increases blood pressure by activating the carotid sinus nerve, which transmits the chemosensory input from carotid bodies (CBs) to the medullary centers, and that the effect of leptin is mediated via Trpm7 (TRP [transient receptor potential] melastatin 7) channels in CB glomus cells. We also found that Trpm7 overexpression and Trpm7 promoter demethylation in CBs correlate positively with the hyperleptinemia and leptin receptor overexpression in CBs. Hence, we postulated that leptin epigenetically regulates Trpm7 expression in CBs. We addressed our hypothesis by using rat adrenal pheochromocytoma (PC12) cells as a model of CB glomus cells. PC12 cells expressing LEPRb (long, active form of leptin receptor) showed dramatic induction of the promoter activity and expression of Trpm7 upon leptin treatment. The increased Trpm7 expression coincided with the reduction of CpG site-specific methylation and trimethylation of H3K27 (H3 [histone 3] K27 [lysine 27]) and the increase of acetylation of H3K27 and trimethylation of H3K4 (H3 lysine 4) at the Trpm7 promoter. The inhibitor of STAT3 (signal transducer and activator of transcription 3) signaling, SD1008, reversed the leptin-induced Trpm7 promoter activity via modulations of the binding of pSTAT3 (phosphorylated STAT3) and DNMT3B (DNA methyltransferase 3B) and modifications of H3K27 and H3K4 at the Trpm7 promoter. Our results suggest that leptin-activated pSTAT3 epigenetically regulates the transcription of Trpm7 through DNA methylation and histone modifications. Because epigenetic changes are reversible, targeting epigenetic modifications of Trpm7 may serve as a new therapeutic approach for the treatment of hypertension in obesity.

Serotonin and chronic hypoxic pulmonary hypertension activate a NADPH oxidase 4 and TRPM2 dependent pathway for pulmonary arterial smooth muscle cell proliferation and migration.

5-Hydroxytryptamine (5-HT)-dependent signaling mediated through its transporters and receptors plays important roles in chronic hypoxic pulmonary hypertension (CHPH), which is associated with aberrant reactive oxygen species (ROS) production. NADPH oxidase 4 (NOX4) is one of the major sources of ROS in pulmonary vasculature, and has been implicated in the development of PH. NOX4 generates H2O2, which can activate the transient receptor potential melastatin 2 (TRPM2) channels, providing Ca2+ signals for cell proliferation and migration. However, the connection between 5-HT, NOX4, ROS and TRPM2 in the context of PH has not been established. Here we examined the level of 5-HT and expression of NOX4 and TRPM2, and their roles in pulmonary arterial smooth muscle cells (PASMCs) proliferation and migration. NOX4 and TRPM2 were upregulated in pulmonary arteries of CHPH rats, which were associated with elevated levels of 5-HT and ROS, and enhanced proliferation and migration in PASMCs. The increase in ROS, and the enhanced proliferation and migration of PASMCs from CHPH rats were mimicked by treating normoxic PASMCs with 5-HT. 5-HT; and CH-induced ROS production were reversed by catalase, the NOX1/NOX4 inhibitor GKT137831, and Nox4 siRNA. 5-HT and H2O2 elicited Ca2+ responses were significantly augmented in CHPH PASMCs; and the augmented Ca2+ responses were obliterated by the 2-Aminoethoxydiphenyl borate (2-APB) and Trpm2-specific siRNA. Moreover, 5-HT and CH-induced proliferation and migration were suppressed by Nox4 or Trpm2 siRNA; and simultaneous transfection of both siRNA did not cause further inhibition. These results suggest that the 5-HT and CH-induced PASMC proliferation and migration were mediated, at least in part, by TRPM2 via activation of NOX4-dependent ROS production; and revealed a novel NOX4-ROS-TRPM2 signaling pathway for the pathogenesis of CHPH.

Poor long-term prognosis in patients admitted with strong suspicion of acute myocardial infarction but discharged with another diagnosis.

BACKGROUND: Characteristics and prognosis of patients admitted with strong suspicion of myocardial infarction (MI) but discharged without an MI diagnosis are not well-described. OBJECTIVES: To compare background characteristics and cardiovascular outcomes in patients discharged with or without MI diagnosis. METHODS: The DETermination of the role of Oxygen in suspected Acute Myocardial Infarction (DETO2X-AMI) trial compared 6629 patients with strong suspicion of MI randomized to oxygen or ambient air. The main composite end-point of this subgroup analysis was the incidence of all-cause death, rehospitalization with MI, heart failure (HF) or stroke during a follow-up of 2.1 years (median; range: 1-3.7 years) irrespective of randomized treatment. RESULTS: 1619 (24%) received a non-MI discharge diagnosis, and 5010 patients (76%) were diagnosed with MI. Groups were similar in age, but non-MI patients were more commonly female and had more comorbidities. At thirty days, the incidence of the composite end-point was 2.8% (45 of 1619) in non-MI patients, compared to 5.0% (250 of 5010) in MI patients with lower incidences in all individual end-points. However, for the long-term follow-up, the incidence of the composite end-point increased in the non-MI patients to 17.7% (286 of 1619) as compared to 16.0% (804 of 5010) in MI patients, mainly driven by a higher incidence of all-cause death, stroke and HF. CONCLUSIONS: Patients admitted with a strong suspicion of MI but discharged with another diagnosis had more favourable outcomes in the short-term perspective, but from one year onwards, cardiovascular outcomes and death deteriorated to a worse long-term prognosis.

Finding and Characterising Active Slip Systems: A Short Review and Tutorial with Automation Tools.

The behaviour of many materials is strongly influenced by the mechanical properties of hard phases, present either from deliberate introduction for reinforcement or as deleterious precipitates. While it is, therefore, self-evident that these phases should be studied, the ability to do so-particularly their plasticity-is hindered by their small sizes and lack of bulk ductility at room temperature. Many researchers have, therefore, turned to small-scale testing in order to suppress brittle fracture and study the deformation mechanisms of complex crystal structures. To characterise the plasticity of a hard and potentially anisotropic crystal, several steps and different nanomechanical testing techniques are involved, in particular nanoindentation and microcompression. The mechanical data can only be interpreted based on imaging and orientation measurements by electron microscopy. Here, we provide a tutorial to guide the collection, analysis, and interpretation of data on plasticity in hard crystals. We provide code collated in our group to help new researchers to analyse their data efficiently from the start. As part of the tutorial, we show how the slip systems and deformation mechanisms in intermetallics such as the Fe7Mo6 µ-phase are discovered, where the large and complex crystal structure precludes determining a priori even the slip planes in these phases. By comparison with other works in the literature, we also aim to identify "best practises" for researchers throughout to aid in the application of the methods to other materials systems.

Magnesium Supplementation Attenuates Pulmonary Hypertension via Regulation of Magnesium Transporters.

Pulmonary hypertension (PH) is characterized by profound vascular remodeling and altered Ca2+ homeostasis in pulmonary arterial smooth muscle cells (PASMCs). Magnesium ion (Mg2+), a natural Ca2+ antagonist and a cofactor for numerous enzymes, is crucial for regulating diverse cellular functions, but its roles in PH remains unclear. Here, we examined the roles of Mg2+ and its transporters in PH development. Chronic hypoxia and monocrotaline induced significant PH in adult male rats. It was associated with a reduction of [Mg2+]i in PASMCs, a significant increase in gene expressions of Cnnm2, Hip14, Hip14l, Magt1, Mmgt1, Mrs2, Nipa1, Nipa2, Slc41a1, Slc41a2 and Trpm7; upregulation of SLC41A1, SLC41A2, CNNM2, and TRPM7 proteins; and downregulation of SLC41A3 mRNA and protein. Mg2+ supplement attenuated pulmonary arterial pressure, right heart hypertrophy, and medial wall thickening of pulmonary arteries, and reversed the changes in the expression of Mg2+ transporters. Incubation of PASMCs with a high concentration of Mg2+ markedly inhibited PASMC proliferation and migration, and increased apoptosis, whereas a low level of Mg2+ produced the opposite effects. siRNA targeting Slc41a1/2, Cnnm2, and Trpm7 attenuated PASMC proliferation and migration, but promoted apoptosis; and Slc41a3 overexpression also caused similar effects. Moreover, siRNA targeting Slc41a1 or high [Mg2+] incubation inhibited hypoxia-induced upregulation and nuclear translocation of NFATc3 in PASMCs. The results, for the first time, provide the supportive evidence that Mg2+ transporters participate in the development of PH by modulating PASMC proliferation, migration, and apoptosis; and Mg2+ supplementation attenuates PH through regulation of Mg2+ transporters involving the NFATc3 signaling pathway.

An astronomically dated record of Earth's climate and its predictability over the last 66 million years.

Much of our understanding of Earth's past climate comes from the measurement of oxygen and carbon isotope variations in deep-sea benthic foraminifera. Yet, long intervals in existing records lack the temporal resolution and age control needed to thoroughly categorize climate states of the Cenozoic era and to study their dynamics. Here, we present a new, highly resolved, astronomically dated, continuous composite of benthic foraminifer isotope records developed in our laboratories. Four climate states-Hothouse, Warmhouse, Coolhouse, Icehouse-are identified on the basis of their distinctive response to astronomical forcing depending on greenhouse gas concentrations and polar ice sheet volume. Statistical analysis of the nonlinear behavior encoded in our record reveals the key role that polar ice volume plays in the predictability of Cenozoic climate dynamics.

Cytochrome P450 Epoxygenase-Dependent Activation of TRPV4 Channel Participates in Enhanced Serotonin-Induced Pulmonary Vasoconstriction in Chronic Hypoxic Pulmonary Hypertension.

Transient receptor potential vanilloid 4 (TRPV4) is a multi-functional non-selective channel expressed in pulmonary vasculatures. TRPV4 contributes to serotonin- (5-HT-) induced pulmonary vasoconstriction and is responsible in part for the enhanced 5-HT response in pulmonary arteries (PAs) of chronic hypoxia mice. Epoxyeicosatrienoic acid (EET) is an endogenous agonist of TRPV4 and is known to regulate vasoreactivity. The levels of EETs, the expression of cytochrome P450 (CYP) epoxygenase for EET production, and epoxide hydrolase for EET degradation are altered by chronic hypoxia. Here, we examined the role of EET-dependent TRPV4 activation in the 5-HT-mediated PA contraction. In PAs of normoxic mice, inhibition of TRPV4 with a specific inhibitor HC-067047 caused a decrease in the sensitivity of 5-HT-induced PA contraction without affecting the maximal contractile response. Application of the cytochrome P450 epoxygenase inhibitor MS-PPOH had no effect on the vasoreactivity to 5-HT. In contrast, inhibition of CYP epoxygenase or TRPV4 both attenuated the 5-HT-elicited maximal contraction to a comparable level in PAs of chronic hypoxic mice. Moreover, the inhibitory effect of MS-PPOH on the 5-HT-induced contraction was obliterated in PAs of chronic hypoxic trpv4-/- mice. These results suggest that TRPV4 contributes to the enhanced 5-HT-induced vasoconstriction in chronic hypoxic PAs, in part via the CYP-EET-TRPV4 pathway. Our results further support the notion that manipulation of TRPV4 function may offer a novel therapeutic strategy for the treatment of hypoxia-related pulmonary hypertension.

Leptin Induces Hypertension Acting on Transient Receptor Potential Melastatin 7 Channel in the Carotid Body.

RATIONALE: Obesity leads to resistant hypertension and mechanisms are poorly understood, but high plasma levels of leptin have been implicated. Leptin increases blood pressure acting both centrally in the dorsomedial hypothalamus and peripherally. Sites of the peripheral hypertensive effect of leptin have not been identified. We previously reported that leptin enhanced activity of the carotid sinus nerve, which transmits chemosensory input from the carotid bodies (CBs) to the medullary centers, and this effect was abolished by nonselective blockers of Trp (transient receptor potential) channels. We searched our mouse CB transcriptome database and found that the Trpm7 (transient receptor potential melastatin 7) channel was the most abundant Trp channel. OBJECTIVE: To examine if leptin induces hypertension acting on the CB Trpm7. METHODS AND RESULTS: C57BL/6J (n=79), leptin receptor (LepRb) deficient db/db mice (n=22), and LepRb-EGFP (n=4) mice were used. CB Trpm7 and LepRb gene expression was determined and immunohistochemistry was performed; CB glomus cells were isolated and Trpm7-like current was recorded. Blood pressure was recorded continuously in (1) leptin-treated C57BL/6J mice with intact and denervated CB; (2) leptin-treated C57BL/6J mice, which also received a nonselective Trpm7 blocker FTY720 administered systemically or topically to the CB area; (3) leptin-treated C57BL/6J mice transfected with Trpm7 small hairpin RNA to the CB, and (4) Leprb deficient obese db/db mice before and after Leprb expression in CB. Leptin receptor and Trpm7 colocalized in the CB glomus cells. Leptin induced a nonselective cation current in these cells, which was inhibited by Trpm7 blockers. Leptin induced hypertension in C57BL/6J mice, which was abolished by CB denervation, Trpm 7 blockers, and Trpm7 small hairpin RNA applied to CBs. Leprb overexpression in CB of Leprb-deficient db/db mice demethylated the Trpm7 promoter, increased Trpm7 gene expression, and induced hypertension. CONCLUSIONS: We conclude that leptin induces hypertension acting on Trmp7 in CB, which opens horizons for new therapy.

Leptin acts in the carotid bodies to increase minute ventilation during wakefulness and sleep and augment the hypoxic ventilatory response.

KEY POINTS: Leptin is a potent respiratory stimulant. A long functional isoform of leptin receptor, LepRb , was detected in the carotid body (CB), a key peripheral hypoxia sensor. However, the effect of leptin on minute ventilation (VE ) and the hypoxic ventilatory response (HVR) has not been sufficiently studied. We report that LepRb is present in approximately 74% of the CB glomus cells. Leptin increased carotid sinus nerve activity at baseline and in response to hypoxia in vivo. Subcutaneous infusion of leptin increased VE and HVR in C57BL/6J mice and this effect was abolished by CB denervation. Expression of LepRb in the carotid bodies of LepRb deficient obese db/db mice increased VE during wakefulness and sleep and augmented the HVR. We conclude that leptin acts on LepRb in the CBs to stimulate breathing and HVR, which may protect against sleep disordered breathing in obesity. ABSTRACT: Leptin is a potent respiratory stimulant. The carotid bodies (CB) express the long functional isoform of leptin receptor, LepRb , but the role of leptin in CB has not been fully elucidated. The objectives of the current study were (1) to examine the effect of subcutaneous leptin infusion on minute ventilation (VE ) and the hypoxic ventilatory response to 10% O2 (HVR) in C57BL/6J mice before and after CB denervation; (2) to express LepRb in CB of LepRb -deficient obese db/db mice and examine its effects on breathing during sleep and wakefulness and on HVR. We found that leptin enhanced carotid sinus nerve activity at baseline and in response to 10% O2 in vivo. In C57BL/6J mice, leptin increased VE from 1.1 to 1.5 mL/min/g during normoxia (P < 0.01) and from 3.6 to 4.7 mL/min/g during hypoxia (P < 0.001), augmenting HVR from 0.23 to 0.31 mL/min/g/Δ FIO2 (P < 0.001). The effects of leptin on VE and HVR were abolished by CB denervation. In db/db mice, LepRb expression in CB increased VE from 1.1 to 1.3 mL/min/g during normoxia (P < 0.05) and from 2.8 to 3.2 mL/min/g during hypoxia (P < 0.02), increasing HVR. Compared to control db/db mice, LepRb transfected mice showed significantly higher VE throughout non-rapid eye movement (20.1 vs. -27.7 mL/min respectively, P < 0.05) and rapid eye movement sleep (16.5 vs 23.4 mL/min, P < 0.05). We conclude that leptin acts in CB to augment VE and HVR, which may protect against sleep disordered breathing in obesity.

Data on measurement of the strain partitioning in a multiphase Zn-Al eutectic alloy.

This paper presents original data related to the research article "Local mechanical properties and plasticity mechanisms in a Zn-Al eutectic alloy" (Wu et al., 2018). The raw data provided here was used for in-situ digital image correlation on the microstructural level using a new method described in the related study. The data includes sample preparation details, image acquisition and data processing. The described approach provides an approach to quantify the local strain distribution and strain partitioning in multiphase microstructures.