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N-myristoyltransferase-1 (NMT1) catalyzes protein myristoylation, a lipid modification that is elevated in cancer cells. NMT1 sustains proliferation and/or survival of cancer cells through mechanisms that are not completely understood. We used genetic and pharmacological inhibition of NMT1 to further dissect the role of this enzyme in cancer, and found an unexpected essential role for NMT1 at promoting lysosomal metabolic functions. Lysosomes mediate enzymatic degradation of vesicle cargo, and also serve as functional platforms for mTORC1 activation. We show that NMT1 is required for both lysosomal functions in cancer cells. Inhibition of NMT1 impaired lysosomal degradation leading to autophagy flux blockade, and simultaneously caused the dissociation of mTOR from the surface of lysosomes leading to decreased mTORC1 activation. The regulation of lysosomal metabolic functions by NMT1 was largely mediated through the lysosomal adaptor LAMTOR1. Accordingly, genetic targeting of LAMTOR1 recapitulated most of the lysosomal defects of targeting NMT1, including defective lysosomal degradation. Pharmacological inhibition of NMT1 reduced tumor growth, and tumors from treated animals had increased apoptosis and displayed markers of lysosomal dysfunction. Our findings suggest that compounds targeting NMT1 may have therapeutic benefit in cancer by preventing mTORC1 activation and simultaneously blocking lysosomal degradation, leading to cancer cell death. [ABSTRACT FROM AUTHOR]

Bronchopulmonary dysplasia (BPD) is potentially one of the most devastating conditions in premature infants with longstanding consequences involving multiple organ systems including adverse effects on pulmonary function and neurodevelopmental outcome. Here we review recent studies in the field to summarize the progress made in understanding in the pathophysiology, prognosis, prevention, and treatment of BPD in the last decade. The work reviewed includes the progress in understanding its pathobiology, genomic studies, ventilatory strategies, outcomes, and therapeutic interventions. We expect that this review will help guide clinicians to treat premature infants at risk for BPD better and lead researchers to initiate further studies in the field. [ABSTRACT FROM AUTHOR]

Introduction: The physiologic vitamin D (VD), 1α,25(OH)D (1,25D) is a local paracrine/autocrine effecter of fetal lung maturation. By stimulating alveolar type II cell and lipofibroblast proliferation and differentiation, parenterally administered 1,25D has been shown to enhance neonatal lung maturation; but due to the potential systemic side effects of the parenteral route, the translational value of these findings might be limited. To minimize the possibility of systemic toxicity, we examined the effects of VD on neonatal lung maturation, when delivered directly to lungs via nebulization. Methods: One-day-old rat pups were administered three different doses of 1,25D and its physiologic precursor 25(OH)D (25D), or the diluent, via nebulization daily for 14 days. Pups were sacrificed for lung, kidneys, and blood collection to determine markers of lung maturation, and serum 25D and calcium levels. Results: Compared to controls, nebulized 25D and 1,25D enhanced lung maturation as evidenced by the increased expression of markers of alveolar epithelial (SP-B, leptin receptor), mesenchymal (PPARγ, C/EBPα), and endothelial (VEGF, FLK-1) differentiation, surfactant phospholipid synthesis, and lung morphology without any significant increases in serum 25D and calcium levels. Conclusions: Inhaled VD is a potentially safe and effective novel strategy to enhance neonatal lung maturation. [ABSTRACT FROM AUTHOR]

Introduction: Pregnant women exposed to tobacco smoke predispose the offspring to many adverse consequences including an altered lung development and function. There is no effective therapeutic intervention to block the effects of smoke exposure on the developing lung. Clinical and animal studies demonstrate that acupuncture can modulate a variety of pathophysiological processes, including those involving the respiratory system; however, whether acupuncture affects the lung damage caused by perinatal smoke exposure is not known. Methods: To determine the effect of acupuncture on perinatal nicotine exposure on the developing lung, pregnant rat dams were administered (1) saline, (2) nicotine, or (3) nicotine + electroacupuncture (EA). Nicotine was administered (1 mg/kg subcutaneously) once a day and EA was applied to both 'Zusanli' (ST 36) points. Both interventions were administered from gestational day 6 to postnatal day 21 (PND21), following which pups were sacrificed. Lungs, blood, and brain were collected to examine markers of lung injury, repair, and hypothalamic pituitary adrenal (HPA) axis. Results: Concomitant EA application blocked nicotine-induced changes in lung morphology, lung peroxisome proliferator-activated receptor γ and wingless-int signaling, two key lung developmental signaling pathways, hypothalamic pituitary adrenal axis (hypothalamic corticotropic releasing hormone and lung glucocorticoid receptor levels), and plasma β-endorphin levels. Conclusions: Electroacupuncture blocks the nicotine-induced changes in lung developmental signaling pathways and the resultant myogenic lung phenotype, known to be present in the affected offspring. We conclude that EA is a promising novel intervention against the smoke exposed lung damage to the developing lung. [ABSTRACT FROM AUTHOR]

Perinatal smoke/nicotine exposure predisposes to chronic lung disease and morbidity. Mitochondrial abnormalities may contribute as the PPARγ pathway is involved in structural and functional airway deficits after perinatal nicotine exposure. We hypothesized perinatal nicotine exposure results in lung mitochondrial dysfunction that can be rescued by rosiglitazone (RGZ; PPARγ receptor agonist). Sprague-Dawley dams received placebo (CON), nicotine (NIC, 1 mg kg), or NIC + RGZ (3 mg kg) daily from embryonic day 6 to postnatal day 21. Parenchymal lung (~10 mg) was taken from adult male offspring for mitochondrial assessment in situ. ADP-stimulated O consumption was less in NIC and NIC + RGZ compared to CON (F[2,14] = 17.8; 4.5 ± 0.8 and 4.1 ± 1.4 vs. 8.8 ± 2.5 pmol s mg; p < 0.05). The respiratory control ratio for ADP, an index of mitochondrial coupling, was reduced in NIC and remediated in NIC + RGZ (F[2,14] = 3.8; p < 0.05). Reduced mitochondrial oxidative capacity and abnormal coupling were evident after perinatal nicotine exposure. RGZ improved mitochondrial function through tighter coupling of oxidative phosphorylation. [ABSTRACT FROM AUTHOR]

Maternal food restriction (MFR) causes intrauterine growth restriction, a known risk factor for developing chronic lung disease. However, it is unknown whether this negative outcome is gender specific or preventable by blocking the MFR-induced hyperglucocorticoidism. Using a well-established rat model, we used metyrapone (MTP), an inhibitor of glucocorticoid synthesis, to study the MFR-induced lung changes on postnatal day (p) 21 in a gender-specific manner. From embryonic day 10 until delivery, pregnant dams were fed either an ad libitum diet or a 50% caloric restricted diet with or without MTP supplementation. Postnatally, the offspring were fed ad libitum from healthy dams until p21. Morphometric, Western blot, and immunohistochemical analysis of the lungs demonstrated that MTP mitigated the MFR-mediated decrease in alveolar count, decrease in adipogenic protein peroxisome proliferator-activated receptor γ, increase in myogenic proteins (fibronectin, α-smooth muscle actin, and calponin), increase in Wnt signaling intermediates (lymphoid enhancer-binding factor 1 and β-catenin), and increase in glucocorticoid receptor (GR) levels. The MFR-induced lung phenotype and the effects of MTP were similar in both genders. To elucidate the mechanism of MFR-induced shift of the adipogenic-to-myogenic phenotype, lung fibroblasts were used to independently study the effects of (1) nutrient restriction and (2) excess steroid exposure. Nutrient deprivation increased myogenic proteins, Wnt signaling intermediates, and GR, all changes blocked by protein supplementation. MTP also blocked, likely by normalizing nicotinamide adenine dinucleotide phosphate levels, the corticosterone-induced increase in myogenic proteins, but had no effect on GR levels. In summary, protein restriction and increased glucocorticoid levels appear to be the key players in MFR-induced lung disease, affecting both genders. [ABSTRACT FROM AUTHOR]

Maternal food restriction (MFR) during pregnancy affects pulmonary surfactant production in the intrauterine growth-restricted (IUGR) offspring through unknown mechanisms. Since pulmonary surfactant production is regulated by maternal and fetal corticosteroid levels, both known to be increased in IUGR pregnancies, we hypothesized that metyrapone (MTP), a glucocorticoid synthesis inhibitor, would block the effects of MFR on surfactant production in the offspring. Three groups of pregnant rat dams were used (1) control dams fed ad libitum; (2) MFR (50% reduction in calories) from days 10 to 22 of gestation; and (3) MFR + MTP in drinking water (0.5 mg/mL), days 11 to 22 of gestation. At 5 months, the MFR offspring weighed significantly more, had reduced alveolar number, increased septal thickness, and decreased surfactant protein and phospholipid synthesis. These MFR-induced effects were normalized by the antiglucocorticoid MTP, suggesting that the stress of MFR causes hypercorticoidism, altering lung structure and function in adulthood. [ABSTRACT FROM AUTHOR]

There is extensive epidemiologic and experimental evidence from both animal and human studies that demonstrates detrimental long-term pulmonary outcomes in the offspring of mothers who smoke during pregnancy. However, the molecular mechanisms underlying these associations are not understood. Therefore, it is not surprising that that there is no effective intervention to prevent the damaging effects of perinatal smoke exposure. Using a biologic model of lung development, homeostasis, and repair, we have determined that in utero nicotine exposure disrupts specific molecular paracrine communications between epithelium and interstitium that are driven by parathyroid hormone-related protein and peroxisome proliferator-activated receptor (PPAR)γ, resulting in transdifferentiation of lung lipofibroblasts to myofibroblasts, i.e., the conversion of the lipofibroblast phenotype to a cell type that is not conducive to alveolar homeostasis, and is the cellular hallmark of chronic lung disease, including asthma. Furthermore, we have shown that by molecularly targeting PPARγ expression, nicotine-induced lung injury can not only be significantly averted, it can also be reverted. The concept outlined by us differs from the traditional paradigm of teratogenic and toxicological effects of tobacco smoke that has been proposed in the past. We have argued that since nicotine alters the normal homeostatic epithelial-mesenchymal paracrine signaling in the developing alveolus, rather than causing totally disruptive structural changes, it offers a unique opportunity to prevent, halt, and/or reverse this process through targeted molecular manipulations. [ABSTRACT FROM AUTHOR]

Despite tremendous advances in neonatology, bronchopulmonary dysplasia (BPD) remains a major cause of morbidity and mortality among premature infants. Any intervention that would reduce the risk of BPD or improve its outcome is likely to have substantial clinical and financial benefits. However, there is a clear lack of an effective agent for the treatment and/or prevention of BPD. This is due to an incomplete understanding of the molecular mechanisms involved in its pathogenesis. Taking a basic biological approach, our laboratory has discovered that disruption of normal alveolar homeostatic signaling is centrally involved in this process. Using a number of in vitro and in vivo models, our laboratory has demonstrated that stabilization of the normal alveolar homeostatic signaling pathway(s) can prevent and/or rescue the molecular injuries caused by the insults that lead to BPD. Here, we review the existing approaches to prevent and treat BPD and then, based on our insights into the pathogenesis of BPD, we propose novel and innovative therapeutic options that impact the disease on a cell/molecular level, unlike most of the current treatments available for BPD. [ABSTRACT FROM AUTHOR]

Nicotine exposure disrupts the parathyroid hormone-related protein (PTHrP)-driven alveolar epithelial-mesenchymal paracrine-signaling pathway, resulting in the transdifferentiation of pulmonary lipofibroblasts (LIFs) to myofibroblasts (MYFs), which seems to be central to altered pulmonary development and function in infants born to mothers who smoke during pregnancy. Modulation of PTHrP-driven signaling can almost completely prevent nicotine-induced LIF-to-MYF transdifferentiation. However, once this process has occurred, whether it can be reversed is not known. Our objective was to determine if nicotine-induced LIF-to-MYF transdifferentiation could be reversed by specifically targeting the PTHrP-mediated alveolar epithelial-mesenchymal paracrine signaling. WI38 cells, a human embryonic pulmonary fibroblast cell line, were initially treated with nicotine for 7 days and LIF-to-MYF transdifferentiation was confirmed by determining the downregulation of the key lipogenic marker, peroxisome proliferator-activated receptor γ (PPARγ) and upregulation of the key myogenic marker, α-smooth muscle actin (αSMA). Because downregulation of the PPARγ signaling pathway is the key determinant of LIF-to-MYF transdifferentiation, cells were treated with three agonists of this pathway, PTHrP, dibutryl cAMP (DBcAMP), or rosiglitazone (RGZ) for 7 days, and the expression of the PTHrP receptor, PPARγ, αSMA, and calponin was determined by Western analysis and immunohistochemistry. Simultaneously, fibroblast function was characterized by measuring their capacity to take up triglycerides. Nicotine-induced LIF-to-MYF transdifferentiation was almost completely reversed by treatment with RGZ, PTHrP, or DBcAMP, as determined by protein and functional assays. Using a specific molecular approach and targeting specific molecular intermediates in the PTHrP signaling pathway, to our knowledge, this for the first time, demonstrates the reversibility of nicotine-induced LIF-to-MYF transdifferentiation, suggesting not only the possibility of prevention but also the potential for reversal of nicotine-induced lung injury. [ABSTRACT FROM AUTHOR]

Due to a lack of understanding of the molecular mechanisms involved in its pathogenesis, bronchopulmonary dysplasia (BPD) still remains a major cause of morbidity and mortality in the premature infant, and there is no effective preventive and/or therapeutic intervention. We have taken a basic biologic approach to elucidate the pathophysiology of BPD and have discovered that disruption of the alveolar Parathyroid Hormone-related Protein (PTHrP) signaling is centrally involved in this process. Further, stabilization of this signaling pathway by using exogenous PTHrP agonists can prevent and/or rescue the molecular injuries caused by insults that lead to BPD. Based upon years of work in this field, here I provide a novel and innovative molecular approach, i.e., exogenous treatment with PTHrP pathway agonists to prevent and/or treat BPD. However, to avoid any later surprises, it is important to emphasize that before translating it into human trials, this approach needs further testing and refinement in animal models. [ABSTRACT FROM AUTHOR]

Objectives: The optimal method for epinephrine administration during neonatal resuscitation is not known. We hypothesized that epinephrine will be delivered more efficiently when administered via a feeding catheter inserted into the endotracheal tube (G-ETT) vs when administered directly into the ETT (D-ETT). Our objectives were to (1) compare the delivery of epinephrine to the distal end of the ETT when administered via D-ETT vs G-ETT; (2) measure the retention of epinephrine within the ETT vs the feeding catheter used for the drug delivery; and (3) compare the delivery of the drug with and without an air flush after administration via C-ETT. Methods: All experiments were performed in vitro, simulating epinephrine administration during neonatal resuscitation, according to the standard guidelines,. Radiolabeled epinephrine, diluted to 1 &mi;Ci/ml, was used and experiments were repeated at least 4 times. Epinephrine administration via D-ETT was followed by one manual breath via a self-inflating bag attached to the ETT. Epinephrine delivery via G-ETT was followed by 1 ml saline flush, and in some experiments, this was also followed by a 1 cm³ air flush. Epinephrine delivery and retention were assessed by measuring the radioactive content of the efficient fluid and that of the ETT or of the feeding catheter used drug delivery. Results: Significantly higher dosage of the drug was delivered when administered via D-ETT vs C-ETT, if air flush following the saline flush after the drug instillation, there was no difference in the amount of epinephrine delivered between the two methods. Retention in the ETT wall or the catheter was < 7.5% of the administered dose with either method. Conclusion: Without an air flush following G-ETT method of epinephrine delivery, higher dosage of the drug is delivered via D-ETT vs G-ETT method. An air flush following the saline flush during G-ETT method improves drug delivery. Given that the G-ETT method is more cumbersome and time consuming, and does not improve drug delivery, D-ETT administration should be the method of choice for epinephrine delivery during neonatal resuscitation. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The use of continuous positive airway pressure (CPAP) in the treatment of a variety of neonatal respiratory conditions is associated with improvement in arterial oxygen saturation, decreased long-term morbidity, and an overall improvement in infant survival. We reasoned that CPAP might change diaphragm length by increasing end-expiratory lung volume (EEV), but the extent to which this occurs has not been assessed. This study was designed to evaluate (1) the extent to which CPAP shortens the diaphragm and (2) the relationship of diaphragm thickness and excursion with arterial oxygen saturation in spontaneously breathing preterm infants. STUDY DESIGN: Ultrasonographically (7.5 MHz transducer), diaphragm thickness and diaphragm excursion were measured in 12 stable preterm infants [birth weight 1120 ± 225 g (mean ± SD); study weight 1187 ± 400 g; gestational age 29 ± 1 week; postnatal age 10 ± 8 days, six males and six females] at three levels of CPAP [1-3, 4-6, and 7-9 cm H[SUB2]O (low, medium, and high, respectively)]. Heart rate, respiratory rate, and arterial oxygen saturation were simultaneously recorded. RESULTS: We found that diaphragm thickness and arterial oxygen saturation increased, and diaphragm excursion decreased significantly at higher levels of CPAP (p < 0.05). The shortening of the diaphragm at the high levels of CPAP, calculated from the increase in diaphragm thickness, was 36% at EEV and 31% at end-inspiratory volume. CONCLUSION: We conclude that the improvement in arterial oxygen saturation with CPAP occurred despite the presence of a shorter and a less mobile diaphragm, and that other physiological and mechanical alterations accompanying the application of CPAP offset its negative effects on diaphragm function. We speculate that with excessive CPAP, however, diaphragm dysfunction along with the previously described adverse hemodynamic effects may outweigh its benefits on oxygenation. [ABSTRACT FROM AUTHOR]

Antenatal corticosteroid administration has been unequivocally demonstrated to reduce neonatal morbidity and mortality. In addition to its well-documented role in reducing respiratory distress syndrome, evidence is accumulating indicating the global maturational effect of this therapy in the growing fetus. New data demonstrates, the hitherto relatively not well known, beneficial effects of this mode of therapy on renal, cardiovascular, gastrointestinal, endocrinal and cerebral maturation. Despite its well proven efficacy and safety, this therapy is used only in a small fraction of eligible mothers. In this article, biological basis of antenatal steroids use, clinical benefits including those to extremely premature infants, indications for their administration, treatment regimens, practice variations in their administration, cost analysis, and some directions for future research are reviewed. It is hoped that given the evidence reviewed in this article, the use of antenatal steroids administration in proper clinical settings will increase with a significant impact in reducing the neonatal morbidity and mortality. [ABSTRACT FROM AUTHOR]

Metabolic syndrome is characterized by disturbances in glucose homeostasis and the development of low-grade systemic inflammation, which increase the risk to develop type 2 diabetes mellitus (T2DM). Type-2 innate lymphoid cells (ILC2s) are a recently discovered immune population secreting Th2 cytokines. While previous studies show how ILC2s can play a critical role in the regulation of metabolic homeostasis in the adipose tissue, a therapeutic target capable of modulating ILC2 activation has yet to be identified. Here, we show that GITR, a member of the TNF superfamily, is expressed on both murine and human ILC2s. Strikingly, we demonstrate that GITR engagement of activated, but not naïve, ILC2s improves glucose homeostasis, resulting in both protection against insulin resistance onset and amelioration of established insulin- resistance. Together, these results highlight the critical role of GITR as a novel therapeutic molecule against T2DM and its fundamental role as an immune checkpoint for activated ILC2s. Type-2 innate lymphoid cells (ILC2s) are an immune population secreting Th2 cytokines playing a role in the regulation of adipose metabolic homeostasis. Here the authors show that engagement of GITR, a member of the TNF superfamily, in activated ILC2s is protective against insulin resistance in both a preventive and a therapeutic manner in the context of obesity. [ABSTRACT FROM AUTHOR]