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Perspective on This Article from Patched1 Inhibits Epidermal Progenitor Cell Expansion and Basal Cell Carcinoma Formation by Limiting Igfbp2 Activity

Basal cell carcinoma (BCC) of the skin is the most common form of cancer, with the majority being caused by mutations in the Patched1 (Ptch1) gene, leading to activation of the Hedgehog (Hh) signaling pathway. Hh signaling is implicated in many tumor types; thus, defining the mechanisms by which Ptch1 regulates tissue proliferation is of paramount importance. Here, we show that the key role of Ptch1 in the skin is to limit the size of the epidermal stem/progenitor compartment and allow hair follicle differentiation. Specifically, loss of Ptch1 leads to the promotion of progenitor cell fate by increasing basal cell proliferation and limiting the progression of basal cells into differentiated hair follicle cell types. Our data indicate that BCCs likely result from hair follicle progenitor cells that, due to Hh signal activation, cannot progress through normal hair follicle differentiation. These data confirm the role of Ptch1 as a negative regulator of epidermal progenitor turnover and also show for the first time that Ptch1 plays a role in the differentiation of the hair follicle lineage. In addition, we show that insulin-like growth factor binding protein 2 (Igfbp2) is upregulated in both murine and human BCCs and that blocking Igfbp2 activity reduces the Hh-mediated expansion of epidermal progenitor cells. We propose that Igfbp2 mediates epidermal progenitor cell expansion and therefore represents an epidermal progenitor cell–specific target of Hh signaling that promotes BCC development. Cancer Prev Res; 3(10); 1222–34. ©2010 AACR.

Advanced age is typically associated with a decrease in cognitive function including impairment in the formation and retention of new memories. The hippocampus is critical for learning and memory, especially spatial learning, and is particularly affected by ageing. With advanced age, multiple neural components can be detrimentally affected including a reduction in the number of neural stem and precursor cells, a decrease in the formation of adult born neurons (neurogenesis), and deficits in neural circuitry, all of which ultimately contribute to impaired cognitive function. Importantly, physical exercise has been shown to ameliorate many of these impairments and is able to improve learning and memory. Relevantly, growth hormone (GH) is an important protein hormone that decreases with ageing and increases following physical exercise. Originally described due to its role in longitudinal growth, GH has now been identified to play several additional key roles, especially in relation to the brain. Indeed, the regular decrease in GH levels following puberty is one of the most well documented components of neuroendocrine ageing. Growth hormone deficiency (GHD) has been described to have adverse effects on brain function, which can be ameliorated via GH replacement therapy. Physical exercise has been shown to increase circulating GH levels. Furthermore, we recently demonstrated the increase in exercise-mediated GH is critical for improved cognitive function in the aged mouse. Here we examine the multiple roles that GH plays, particularly in the aged brain and following trauma, irradiation and stroke, and how increasing GH levels can ameliorate deficits in cognition.

Growth hormone (GH) acts via JAK2 and LYN to regulate growth, metabolism, and neural function. However, the relationship between these tyrosine kinases remains enigmatic. Through an interdisciplinary approach combining cell biology, structural biology, computation, and single-particle tracking on live cells, we find overlapping LYN and JAK2 Box1-Box2-binding regions in GH receptor (GHR). Our data implicate direct competition between JAK2 and LYN for GHR binding and imply divergent signaling profiles. We show that GHR exhibits distinct mobility states within the cell membrane and that activation of LYN by GH mediates GHR immobilization, thereby initiating its nanoclustering in the membrane. Importantly, we observe that LYN mediates cytokine receptor degradation, thereby controlling receptor turnover and activity, and this applies to related cytokine receptors. Our study offers insight into the molecular interactions of LYN with GHR and highlights important functions for LYN in regulating GHR nanoclustering, signaling, and degradation, traits broadly relevant to many cytokine receptors. Growth hormone (GH) acts via JAK2 and LYN to regulate growth, metabolism, and neural function. However, the relationship between these tyrosine kinases remains enigmatic. Through an interdisciplinary approach combining cell biology, structural biology, computation, and single-particle tracking on live cells, we find overlapping LYN and JAK2 Box1-Box2-binding regions in GH receptor (GHR). Our data implicate direct competition between JAK2 and LYN for GHR binding and imply divergent signaling profiles. We show that GHR exhibits distinct mobility states within the cell membrane and that activation of LYN by GH mediates GHR immobilization, thereby initiating its nanoclustering in the membrane. Importantly, we observe that LYN mediates cytokine receptor degradation, thereby controlling receptor turnover and activity, and this applies to related cytokine receptors. Our study offers insight into the molecular interactions of LYN with GHR and highlights important functions for LYN in regulating GHR nanoclustering, signaling, and degradation, traits broadly relevant to many cytokine receptors.

Vascular anomalies are highly variable in their angioarchitecture, location, and flow dynamics. An individualized, multidisciplinary approach to treatment is required, focusing on improving patient quality of life. With appropriate percutaneous or endovascular treatment, patient satisfaction following interventional therapy is generally high, acknowledging that a complete cure may not always be possible.

The isostructural heteroanionic compounds β-LiAsS

Spin-orbit coupling enables the realization of topologically nontrivial ground states. As spin-orbit coupling increases with increasing atomic number, compounds featuring heavy elements, such as lead, offer a pathway toward creating new topologically nontrivial materials. By employing a high-pressure flux synthesis method, we synthesized single crystals of Ni

When creating training data for machine-learned interatomic potentials (MLIPs), it is common to create initial structures and evolve them using molecular dynamics to sample a larger configuration space. We benchmark two other modalities of evolving structures, contour exploration and dimer-method searches against molecular dynamics for their ability to produce diverse and robust training density functional theory data sets for MLIPs. We also discuss the generation of initial structures which are either from known structures or from random structures in detail to further formalize the structure-sourcing processes in the future. The polymorph-rich zirconium-oxygen composition space is used as a rigorous benchmark system for comparing the performance of MLIPs trained on structures generated from these structural evolution methods. Using Behler-Parrinello neural networks as our machine-learned interatomic potential models, we find that contour exploration and the dimer-method searches are generally superior to molecular dynamics in terms of spatial descriptor diversity and statistical accuracy., Comment: 13 pages, 15 figures, 4 tables

Background and Aims Growth hormone (GH) is important for liver regeneration after partial hepatectomy (PHx). We investigated this process in C57BL/6 mice that express different forms of the GH receptor (GHR) with deletions in key signaling domains. Approach and Results PHx was performed on C57BL/6 mice lacking GHR (Ghr −/−), disabled for all GH‐dependent Janus kinase 2 signaling (Box1 −/−), or lacking only GH‐dependent signal transducer and activator of transcription 5 (STAT5) signaling (Ghr391 −/−), and wild‐type littermates. C57BL/6 Ghr −/−mice showed striking mortality within 48 hours after PHx, whereas Box1 −/− or Ghr391 −/− mice survived with normal liver regeneration. Ghr −/− mortality was associated with increased apoptosis and elevated natural killer/natural killer T cell and macrophage cell markers. We identified H2‐Bl, a key immunotolerance protein, which is up‐regulated by PHx through a GH‐mediated, Janus kinase 2–independent, SRC family kinase–dependent pathway. GH treatment was confirmed to up‐regulate expression of the human homolog of H2‐Bl (human leukocyte antigen G [HLA‐G]) in primary human hepatocytes and in the serum of GH‐deficient patients. We find that injury‐associated innate immune attack by natural killer/natural killer T cell and macrophage cells are instrumental in the failure of liver regeneration, and this can be overcome in Ghr −/− mice by adenoviral delivery of H2‐Bl or by infusion of HLA‐G protein. Further, H2‐Bl knockdown in wild‐type C57BL/6 mice showed elevated markers of inflammation after PHx, whereas Ghr −/− backcrossed on a strain with high endogenous H2‐Bl expression showed a high rate of survival following PHx. Conclusions GH induction of H2‐Bl expression is crucial for reducing innate immune‐mediated apoptosis and promoting survival after PHx in C57BL/6 mice. Treatment with HLA‐G may lead to improved clinical outcomes following liver surgery or transplantation.

Disruption of endocrine hormonal balance (i.e., increased levels of insulin, and reduced levels of growth hormone, GH) often occurs in pre-obesity and obesity. Using distinct intracellular signaling pathways to control cell and body metabolism, GH and insulin also regulate each other's secretion to maintain overall metabolic homeostasis. Therefore, a comprehensive understanding of insulin and GH balance is essential for understanding endocrine hormonal contributions to energy storage and utilization. In this review we summarize the actions of, and interactions between, insulin and GH at the cellular level, and highlight the association between the insulin/GH ratio and energy metabolism, as well as fat accumulation. Use of the [insulin]:[GH] ratio as a biomarker for predicting the development of obesity is proposed.

Background The optimal treatment for acute stroke attributable to isolated cervical internal carotid artery occlusion without intracranial target is unclear. The purpose of our study was to examine whether endovascular therapy for acute stroke attributable to isolated cervical internal carotid artery occlusion was associated with improved clinical outcome. Methods We identified patients from 2 comprehensive stroke centers during the period January 2009 to December 2019, with acute ischemic stroke attributable to cervical internal carotid artery occlusion without an intracranial occlusion. We categorized patients into 2 groups: endovascular therapy and medical therapy. Clinical outcome (modified Rankin scale score at 90 days poststroke) was compared between the 2 groups. Results Seventy‐three patients were included (26 women [36%]; median age, 69 [interquartile range (IQR), 60–80] years; median National Institutes of Health Stroke Scale score, 11 [IQR, 5–16]). Of these, 40 patients received endovascular therapy, and 33 patients were managed with medical therapy alone. The endovascular therapy group had a significantly higher median National Institutes of Health Stroke Scale score on presentation (13 versus 3; P P =0.002). There were no other significant differences in baseline characteristics between the 2 groups. Good clinical outcome (modified Rankin scale score 0–2 at 90 days or no decline in modified Rankin scale score from baseline at 90 days) was seen in 73% of the endovascular therapy group compared with the 61% of the medical management group (odds ratio [OR] for good outcome, 1.7 [95% CI, 0.64–4.6]), despite the large discrepancy in baseline stroke severity. When restricted to patients with presenting National Institutes of Health Stroke Scale score ≥6, endovascular therapy was associated with higher rates of good clinical outcome (66% versus 18%; OR for good outcome, 9.0 [95% CI, 1.65–49.0]). Conclusions Endovascular therapy in isolated cervical internal carotid artery occlusion may be associated with improved outcome when compared with medical therapy. However, the significant differences in baseline characteristics between the groups limit interpretation. Randomized controlled trials are necessary.

Background There is a clinical need for a guide catheter with combined stability and navigability, which can be used in a biaxial system for neuroendovascular procedures in place of triaxial systems. Objective To assess the safety and feasibility of the Q’Apel Medical Wahoo Hybrid Access System, a dual-mode 0.072″ internal diameter guide catheter, in a range of neuroendovascular procedures. Methods We performed a retrospective analysis of consecutive cases from a high-volume tertiary center in which the Wahoo Hybrid Access System was used as the guide catheter. Characteristics of the patients, vascular lesions, procedure, and procedural complications were assessed. Results A total of 102 patients were included for analysis. Vascular lesions were in the anterior circulation in 90 of 102 (88%), and posterior circulation in 12 of 102 (12%). Eighty-four cases were ruptured or unruptured aneurysm embolization procedures, the majority being balloon-assisted coiling (42%) and flow diversion (42%). All cases, including flow diversion, were performed as a biaxial system. There were no instances of prolapse of the catheter beyond the arterial segment in which it was initially placed. The procedure was able to be performed to completion in 101 of 102 (99%) cases. Thromboembolic complications occurred in 5 of 102 (5%); causality in two cases was unrelated to the guide catheter, and three were indeterminate. Conclusions The Wahoo guide catheter is safe and feasible when used in a variety of neuroendovascular procedures. It can accommodate a range of devices, can be safely navigated into distal vasculature, and provides support for a range of procedures, including those which traditionally require triaxial support.

The second quantum revolution harnesses exquisite quantum control for a slate of diverse applications including sensing, communication, and computation. Of the many candidates for building quantum systems, molecules offer both tunability and specificity, but the principles to enable high temperature operation are not well established. Spin–lattice relaxation, represented by the time constant T₁, is the primary factor dictating the high temperature performance of quantum bits (qubits), and serves as the upper limit on qubit coherence times (T₂). For molecular qubits at elevated temperatures (>100 K), molecular vibrations facilitate rapid spin–lattice relaxation which limits T₂ to well below operational minimums for certain quantum technologies. Here we identify the effects of controlling orbital angular momentum through metal coordination geometry and ligand rigidity via π-conjugation on T₁ relaxation in three four-coordinate Cu²⁺ S = ½ qubit candidates: bis(N,N′-dimethyl-4-amino-3-penten-2-imine) copper(II) (Me₂Nac)₂ (1), bis(acetylacetone)ethylenediamine copper(II) Cu(acacen) (2), and tetramethyltetraazaannulene copper(II) Cu(tmtaa) (3). We obtain significant T₁ improvement upon changing from tetrahedral to square planar geometries through changes in orbital angular momentum. T₁ is further improved with greater π-conjugation in the ligand framework. Our electronic structure calculations reveal that the reduced motion of low energy vibrations in the primary coordination sphere slows relaxation and increases T₁. These principles enable us to report a new molecular qubit candidate with room temperature T₂ = 0.43 μs, and establishes guidelines for designing novel qubit candidates operating above 100 K.

Summary Hippocampal function is critical for spatial and contextual learning, and its decline with age contributes to cognitive impairment. Exercise can improve hippocampal function, however, the amount of exercise and mechanisms mediating improvement remain largely unknown. Here, we show exercise reverses learning deficits in aged (24 months) female mice but only when it occurs for a specific duration, with longer or shorter periods proving ineffective. A spike in the levels of growth hormone (GH) and a corresponding increase in neurogenesis during this sweet spot mediate this effect because blocking GH receptor with a competitive antagonist or depleting newborn neurons abrogates the exercise-induced cognitive improvement. Moreover, raising GH levels with GH-releasing hormone agonist improved cognition in nonrunners. We show that GH stimulates neural precursors directly, indicating the link between raised GH and neurogenesis is the basis for the substantially improved learning in aged animals., Graphical abstract, Highlights • Only specific periods of exercise restores spatial learning in aged mice • Increased growth hormone (GH) mediates improved learning by activating neurogenesis • Neurogenesis is required for exercise-mediated improvement in learning • Identification of mechanisms regulating GH-mediated improvements in learning, Age; Endocrine system physiology; Neuroscience

The mixed cation compounds Na

The only treatment tested for growth hormone receptor (GHR) defective Laron Syndrome (LS) is injections of recombinant insulin-like-growth factor 1 (rhIGF1). The response is suboptimal and associated with progressive obesity. In this study, we treated 4–5-week-old Laron dwarf mice (GHR−/−) with an adeno-associated virus expressing murine GHR (AAV-GHR) injection at a dose of 4 × 1010 vector genome per mouse. Serum growth hormone (GH) levels decreased, and GH-responsive IGF1, IGF binding protein 3 (IGFBP3) and acid labile subunit (ALS) increased. There was a significant but limited increase in body weight and length, similar to the response to rhIGF1 treatment in LS patients. All the major organs increased in weight except the brain. Our study is the first to use gene therapy to treat GH-receptor deficiency. We propose that gene therapy with AAV-GHR may eventually be useful for the treatment of human LS.

We would like to provide information that address the Letter to Editors submitted on 17 July 2020 by Lin and Yan regarding our publication.(1) We have provided a response to each point raised by the authors below.

Background and Purpose— Reversal of dabigatran before intravenous thrombolysis in patients with acute ischemic stroke has been well described using alteplase but experience with intravenous tenecteplase is limited. Tenecteplase seems at least noninferior to alteplase in patients with intracranial large vessel occlusion. We report on the experience of dabigatran reversal before tenecteplase thrombolysis for acute ischemic stroke. Methods— We included consecutive patients with ischemic stroke receiving dabigatran prestroke treated with intravenous tenecteplase after receiving idarucizumab. Patients were from 2 centers in New Zealand and Australia. We reported the clinical, laboratory, and radiological characteristics and their functional outcome. Results— We identified 13 patients receiving intravenous tenecteplase after dabigatran reversal. Nine (69%) were male, median age was 79 (interquartile range, 69–85) and median baseline National Institutes of Health Stroke Scale score was 6 (interquartile range, 4–21). Atrial fibrillation was the indication for dabigatran therapy in all patients. All patients had a prolonged thrombin clotting time (median, 80 seconds [interquartile range, 57–113]). Seven patients with large vessel occlusion were referred for endovascular thrombectomy, 2 of these patients (29%) had early recanalization with tenecteplase abrogating thrombectomy. No patients had parenchymal hemorrhage or symptomatic hemorrhagic transformation. Favorable functional outcome (modified Rankin Scale score, 0–2) occurred in 8 (62%) patients. Two deaths occurred from large territory infarction. Conclusions— Our experience suggests intravenous thrombolysis with tenecteplase following dabigatran reversal using idarucizumab may be safe in selected patients with acute ischemic stroke. Further studies are required to more precisely estimate the efficacy and risk of clinically significant hemorrhage.

Both humans and mice lacking functional growth hormone (GH) receptors are known to be resistant to cancer. Further, autocrine GH has been reported to act as a cancer promoter. Here we present the first example of a variant of the GH receptor (GHR) associated with cancer promotion, in this case lung cancer. We show that the GHRP495T variant located in the receptor intracellular domain is able to prolong the GH signal in vitro using stably expressing mouse pro-B-cell and human lung cell lines. This is relevant because GH secretion is pulsatile, and extending the signal duration makes it resemble autocrine GH action. Signal duration for the activated GHR is primarily controlled by suppressor of cytokine signalling 2 (SOCS2), the substrate recognition component of the E3 protein ligase responsible for ubiquitinylation and degradation of the GHR. SOCS2 is induced by a GH pulse and we show that SOCS2 binding to the GHR is impaired by a threonine substitution at Pro 495. This results in decreased internalisation and degradation of the receptor evident in TIRF microscopy and by measurement of mature (surface) receptor expression. Mutational analysis showed that the residue at position 495 impairs SOCS2 binding only when a threonine is present, consistent with interference with the adjacent Thr494. The latter is key for SOCS2 binding, together with nearby Tyr487, which must be phosphorylated for SOCS2 binding. We also undertook nuclear magnetic resonance spectroscopy approach for structural comparison of the SOCS2 binding scaffold Ile455-Ser588, and concluded that this single substitution has altered the structure of the SOCS2 binding site. Importantly, we find that lung BEAS-2B cells expressing GHRP495T display increased expression of transcripts associated with tumour proliferation, epithelial-mesenchymal transition and metastases (TWIST1, SNAI2, EGFR, MYC and CCND1) at 2 h after a GH pulse. This is consistent with prolonged GH signalling acting to promote cancer progression in lung cancer.Oncogene advance online publication, 2 October 2017; doi:10.1038/onc.2017.352.

Statin-induced necrotising autoimmune myopathy (NAM) is a rare but disabling complication of statin therapy. Data regarding treatment and outcomes in these patients is sparse. We retrospectively identified those patients with a diagnosis of statin-induced NAM who were managed in a single-tertiary referral centre from January 2014 to January 2017. Data regarding clinical features, serology, antibody status and functional outcome was collected. We identified 16 patients diagnosed with statin-induced NAM. Truncal weakness was present in 9/16 patients, of which one patient presented with camptocormia. Following treatment, the mean improvement in the 8-point manual muscle test (MMT8) score was 11 points (range 1-25). Antibodies to 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) were detected in 8/14 patients tested. Of patients who were HMGCR positive, 7/8 had significant truncal weakness, compared with 1/6 who were anti-HMGCR negative. In 4/7 patients who had anti-HMGCR retested following treatment, these antibodies subsequently became undetectable. The disappearance of anti-HMGCR was accompanied by sustained clinical improvement in all four patients. The mean Karnofsky Performance Status (KPS) prior to diagnosis was 89/100, and at latest follow-up had fallen to 68/100. We report a novel association of anti-HMGCR antibodies with truncal weakness in patients with statin-induced NAM. Functional impairments persist despite normalisation of muscle strength. Anti-HMGCR antibodies may disappear with treatment, paralleled by clinical remission of disease. Further prospective clinical trials are needed to determine optimal management strategies for statin-induced NAM.

Growth hormone (GH) has an important function as an insulin antagonist with elevated insulin sensitivity evident in humans and mice lacking a functional GH receptor (GHR). We sought the molecular basis for this sensitivity by utilizing a panel of mice possessing specific deletions of GHR signaling pathways. Metabolic clamps and glucose homeostasis tests were undertaken in these obese adult C57BL/6 male mice, which indicated impaired hepatic gluconeogenesis. Insulin sensitivity and glucose disappearance rate were enhanced in muscle and adipose of mice lacking the ability to activate the signal transducer and activator of transcription (STAT)5 via the GHR (Ghr-391(−/−)) as for GHR-null (GHR(−/−)) mice. These changes were associated with a striking inhibition of hepatic glucose output associated with altered glycogen metabolism and elevated hepatic glycogen content during unfed state. The enhanced hepatic insulin sensitivity was associated with increased insulin receptor β and insulin receptor substrate 1 activation along with activated downstream protein kinase B signaling cascades. Although phosphoenolpyruvate carboxykinase (Pck)-1 expression was unchanged, its inhibitory acetylation was elevated because of decreased sirtuin-2 expression, thereby promoting loss of PCK1. Loss of STAT5 signaling to defined chromatin immunoprecipitation targets would further increase lipogenesis, supporting hepatosteatosis while lowering glucose output. Finally, up-regulation of IL-15 expression in muscle, with increased secretion of adiponectin and fibroblast growth factor 1 from adipose tissue, is expected to promote insulin sensitivity.—Chhabra, Y., Nelson, C. N., Plescher, M., Barclay, J. L., Smith, A. G., Andrikopoulos, S., Mangiafico, S., Waxman, D. J., Brooks, A. J., Waters, M. J. Loss of growth hormone–mediated signal transducer and activator of transcription 5 (STAT5) signaling in mice results in insulin sensitivity with obesity.

A substantial body of evidence supports a role for the growth hormone (GH)-IGF-1 axis in cancer incidence and progression. This includes epidemiological evidence relating elevated plasma IGF-1 to cancer incidence as well as a lack of cancers in GH/IGF-1 deficiency. Rodent models lacking GH or its receptor are strikingly resistant to the induction of a wide range of cancers, and treatment with the GH antagonist pegvisomant slows tumor progression. While GH receptor expression is elevated in many cancers, autocrine GH is present in several types, and overexpression of autocrine GH can induce cell transformation. While the mechanism of autocrine action is not clear, it does involve both STAT5 and STAT3 activation, and probably nuclear translocation of the GH receptor. Development of a more potent GH receptor antagonist or secretion inhibitor is warranted for cancer therapy.

Growth hormone (GH) is a major regulator of postnatal growth and metabolism. There are extensive clinical applications for GH or its antagonists, including treatments for dwarfism, cancer and metabolic wasting. Owing to this, there is considerable interest in the mechanisms of GH receptor (GHR) activation. It is conventionally thought that GH induces dimerization of two GHR monomers, which initiates intracellular signaling cascades. However, recent studies have provided evidence for a ligand-induced conformational change within constitutively dimerized GHRs being responsible for activating signaling pathways. This review will relate the new model of GHR activation to the activation of related cytokine receptors and discuss the implication of this new model for the design of small GH mimetics and antagonists for therapeutic use.

Ancient granite columns have been a pervasive element in the architecture of Rome since the Imperial era. However, in the fifteenth century, just as the effort to revive Antiquity intensified, these ubiquitous and durable ancient columns fell out of use. It was instead the stone travertine that became the columnar material of choice. Yet, just as quickly as this change occurred, within an exceptionally short period of thirty years, beginning with the construction of the Palazzo della Cancelleria courtyard, Rome saw a renascence in their application. While little has been made of this material shift, this article argues that the sudden extensive employment of spoliated granite columns was a crucial component in the recovery of a distinctly local Roman Antiquity. It was through the use and transformation of spolia that builders and patrons attempted to create an architecture that not only recalled Antiquity, but resubstantiated it, literally making it whole again.

Objective The anti-obesity actions of growth hormone (GH) led us to investigate if GH signaling is able to regulate beige/brite fat development of white adipose tissue (WAT). Methods We studied WAT in GHR-391 mice engineered to be unable to activate STAT5 in response to GH, in mice with adipose specific deletion of GHR, in GHR−/− mice and in bGH transgenic mice. QPCR, immunoblots and immunohistochemistry were used to characterize WAT. The in vivo effects of β-3 adrenergic activation with CL-316,243 and that of FGF21 infusion were also studied. Results GHR-391 mice had lower surface temperature than WT, with deficiency in β-oxidation and beiging transcripts including Ucp1. Oxidative phosphorylation complex subunit proteins were decreased dramatically in GHR-391 inguinal white adipose tissue (iWAT), but increased in bGH iWAT, as were proteins for beige/brown markers. In accord with its lack of β-3 adrenergic receptors, iWAT of GHR-391 mice did not beige in response to administration of the β-3 specific agonist CL-316,243 in contrast to WT mice. GHR-391 mice are deficient in FGF21, but unlike WT, infusion of the purified protein was without effect on extent of beiging. Finally, fat-specific deletion of the GHR replicated the loss of beiging associated transcripts. Conclusion In addition to promoting lipolysis, our study suggests that GH is able to promote formation of beige adipose tissue through activation of STAT5 and induction of Adrb3. This sensitizes WAT to adrenergic input, and may contribute to the anti-obesity actions of GH.

Growth hormone (GH) and structurally related cytokines regulate a great number of physiological and pathological processes. They do this by coupling their single transmembrane domain (TMD) receptors to cytoplasmic tyrosine kinases, either as homodimers or heterodimers. Recent studies have revealed that many of these receptors exist as constitutive dimers rather than being dimerized as a consequence of ligand binding, which has necessitated a new paradigm for describing their activation process. In the present study, we describe a model for activation of the tyrosine kinase Janus kinase 2 (JAK2) by the GH receptor homodimer based on biochemical data and molecular dynamics simulations. Binding of the bivalent ligand reorientates and rotates the receptor subunits, resulting in a transition from a form with parallel TMDs to one where the TMDs separate at the point of entry into the cytoplasm. This movement slides the pseudokinase inhibitory domain of one JAK kinase away from the kinase domain of the other JAK within the receptor dimer–JAK complex, allowing the two kinase domains to interact and trans-activate. This results in phosphorylation and activation of STATs and other signalling pathways linked to this receptor which then regulate postnatal growth, metabolism and stem cell activation. We believe that this model will apply to most if not all members of the class I cytokine receptor family, and will be useful in the design of small antagonists and agonists of therapeutic value.

Migraine aura is a common stroke mimic. We hypothesised that some patients with typical migraine aura symptoms might have embolic stroke detected as the precipitant. We identified fourteen patients who presented with symptoms consistent with a clinical diagnosis of migraine aura, but demonstrated subsequent evidence of acute infarction on magnetic resonance imaging (MRI). In all patients, migraine aura symptoms were not directly attributable to the vascular lesion on MRI. 50% of patients were classified as having an embolic stroke of undetermined source. Of these, a patent foramen ovale was identified in 4/5 of those who underwent transoesophageal echocardiogram, with large right-to-left shunt demonstrated in three. The results from our cohort suggest that migraine aura can be the presenting feature of acute ischaemic stroke, with local ischaemia presumably triggering a widely migrating cortical wave of spreading depolarization.

Pemetrexed is a new-generation antifolate drug, now widely used in patients with non-small cell lung cancer (NSCLC). We report a case of pemetrexed-induced interstitial pneumonitis, and review the literature of eight previously reported cases. As pemetrexed is now a widely used chemotherapeutic agent, it is important to be aware of rare adverse events related to its administration.

SummaryCaveolae and caveolin-1 (CAV1) have been linked to several cellular functions. However, a model explaining their roles in mammalian tissues in vivo is lacking. Unbiased expression profiling in several tissues and cell types identified lipid metabolism as the main target affected by CAV1 deficiency. CAV1−/− mice exhibited impaired hepatic peroxisome proliferator-activated receptor α (PPARα)-dependent oxidative fatty acid metabolism and ketogenesis. Similar results were recapitulated in CAV1-deficient AML12 hepatocytes, suggesting at least a partial cell-autonomous role of hepatocyte CAV1 in metabolic adaptation to fasting. Finally, our experiments suggest that the hepatic phenotypes observed in CAV1−/− mice involve impaired PPARα ligand signaling and attenuated bile acid and FXRα signaling. These results demonstrate the significance of CAV1 in (1) hepatic lipid homeostasis and (2) nuclear hormone receptor (PPARα, FXRα, and SHP) and bile acid signaling.

Pathological changes associated with obesity are thought to contribute to GH deficiency. However, recent observations suggest that impaired GH secretion relative to excess calorie consumption contributes to progressive weight gain and thus may contribute to the development of obesity. To clarify this association between adiposity and GH secretion, we investigated the relationship between pulsatile GH secretion and body weight; epididymal fat mass; and circulating levels of leptin, insulin, non-esterified free fatty acids (NEFAs), and glucose. Data were obtained from male mice maintained on a standard or high-fat diet. We confirm the suppression of pulsatile GH secretion following dietary-induced weight gain. Correlation analyses reveal an inverse relationship between measures of pulsatile GH secretion, body weight, and epididymal fat mass. Moreover, we demonstrate an inverse relationship between measures of pulsatile GH secretion and circulating levels of leptin and insulin. The secretion of GH did not change relative to circulating levels of NEFAs or glucose. We conclude that impaired pulsatile GH secretion in the mouse occurs alongside progressive weight gain and thus precedes the development of obesity. Moreover, data illustrate key interactions between GH secretion and circulating levels of insulin and reflect the potential physiological role of GH in modulation of insulin-induced lipogenesis throughout positive energy balance.

Context: Recombinant human GH (rhGH) therapy in Prader-Willi syndrome (PWS) has been used by the medical community and advocated by parental support groups since its approval in the United States in 2000 and in Europe in 2001. Its use in PWS represents a unique therapeutic challenge that includes treating individuals with cognitive disability, varied therapeutic goals that are not focused exclusively on increased height, and concerns about potential life-threatening adverse events. Objective: The aim of the study was to formulate recommendations for the use of rhGH in children and adult patients with PWS. Evidence: We performed a systematic review of the clinical evidence in the pediatric population, including randomized controlled trials, comparative observational studies, and long-term studies (>3.5 y). Adult studies included randomized controlled trials of rhGH treatment for ≥6 months and uncontrolled trials. Safety data were obtained from case reports, clinical trials, and pharmaceutical registries. Methodology: Forty-three international experts and stakeholders followed clinical practice guideline development recommendations outlined by the AGREE Collaboration (www.agreetrust.org). Evidence was synthesized and graded using a comprehensive multicriteria methodology (EVIDEM) (http://bit.ly.PWGHIN). Conclusions: Following a multidisciplinary evaluation, preferably by experts, rhGH treatment should be considered for patients with genetically confirmed PWS in conjunction with dietary, environmental, and lifestyle interventions. Cognitive impairment should not be a barrier to treatment, and informed consent/assent should include benefit/risk information. Exclusion criteria should include severe obesity, uncontrolled diabetes mellitus, untreated severe obstructive sleep apnea, active cancer, or psychosis. Clinical outcome priorities should vary depending upon age and the presence of physical, mental, and social disability, and treatment should be continued for as long as demonstrated benefits outweigh the risks. Copyright

The growth hormone receptor (GHR) has been the archetype for the class I cytokine receptor family. The original paradigm for how growth hormone (GH) binding to the GHR led to activation of the associated JAK2 was based on biophysical and structural studies over 20 years ago which showed that growth hormone binding to the extracellular domain of the receptor occurred in a sequential fashion, first binding to a high affinity site on a single receptor (site 1) and then binding to a lower affinity site (site 2) on a second receptor. We propose a new model for JAK2 activation by the growth hormone receptor. We utilised multiple approaches to define this model including FRET to monitor positioning of the JAK2 binding motif, leucine-zipper receptor constructs to control receptor transmembrane helix position, atomistic modelling of TM helix interactions and docking of JAK2 kinase and inhibitory pseudokinase crystal structures with an opposing pair in trans. Surprisingly, we identified that receptor activation induces a separation of its JAK2 binding motifs which leads to removal of the pseudokinase domain from the kinase domain of the partner JAK2 and pairing of the two kinase domains, facilitating trans-activation. In addition, we have recently shown that the receptor intracellular domain is intrinsically disordered and has specific interactions with the lipids of the inner membrane. This model of receptor activation may represent a common mechanism to other class I cytokine receptors.

T his study proposes a critical revision of a recent trend in Renaissance scholarship.1 Over the last thirty years, scholars have increasingly argued that the rise of printing and the illustrated printed treatise was a transformative development in the history of architecture. Specifically, Mario Carpo has influentially asserted that mechanical reproduction created stable, authoritatively identical reproductions that removed the creative drift inherent in a system of drawn copies. In doing so, the printed treatise, in particular that of Sebastiano Serlio, codified a new canon of easily reproducible, standardized orders and marginalized a fluid sketchbook tradition built on the practice of copying drawings, especially those of antiquity. The printed treatise by extension framed a series of formal models within a work of architectural theory defined by rules of composition and authorial agency. In sum, according to this paradigm, print was an agent of change that at its most basic level attempted to impose columnar order beginning in 1537 with the first installment of Serlio’s treatise.2 Counter to this argument stands a series of single-sheet engravings of column capitals, bases, and cornices, examples of which the architect Giovan Battista Aleotti (1546–1636), also known as L’Argenta, assembled in an album now in Ferrara.3 Described by the architect as “fragments of each order that wandered as prints and were collected elsewhere by the architect L’Argenta,” Aleotti arranged these printed fragments by columnar order, interleaved between sections of Vignola’s Regola delli cinque ordini d’architettura (1562), and even transformed them into an entire architectural composition (Figure 1).4 While these engravings, found outside of treatises and produced primarily by unknown engravers, have often been relegated to footnotes and separated from their original context, they are evidence that from the very beginning of the sixteenth century, printing unleashed a plethora of varied models …

Fasting results in the mobilization of adipose stores and the elevation of levels of free fatty acids (FFA). In humans, this process is driven by a release in GH. Little is known regarding the role of GH in modulating this process during early stages of fasting in the mouse. Confirmation of the role of GH in modulating FFA release in the fasting mouse is of particular importance given the frequent use of mouse models to study metabolic mechanisms. Here, we correlate the initial release of FFA throughout fasting in mice with pulsatile GH secretion. Observations illustrate the rapid release of FFA in response to food withdrawal. This does not correlate with a rise in GH secretion. Rather, we observed a striking loss in pulsatile secretion of GH throughout the first 6 h of fasting, suggesting that GH does not modulate the initial release of FFA in the mouse in response to fasting. This was confirmed in GH receptor knockout mice, in which we observed a robust fasting-induced rise in FFA. We further illustrate the dynamic relationship between the orexigenic and anorexigenic hormones ghrelin and leptin during fasting in the mouse. Our findings show an initial suppression of leptin and the eventual rise in circulating levels of acyl-ghrelin with fasting. However, altered acyl-ghrelin and leptin secretion occurs well after the rise in FFA and the suppression of GH secretion. Consequently, we conclude that although acyl-ghrelin and leptin may modulate the physiological response to drive food intake, these changes do not contribute to the initial loss of pulsatile GH secretion. Rather, it appears that the suppression of GH secretion in fasting may occur in response to an elevation in fasting levels of FFA or physiological stress. Observations highlight a divergent role for GH in modulating FFA release between man and mouse.

GH receptor (GHR) mediates the anabolic and metabolic effects of GH. We previously characterized a monoclonal antibody (anti-GHR(ext-mAb)) that reacts with subdomain 2 of the rabbit GHR extracellular domain (ECD) and is a conformation-specific inhibitor of GH signaling in cells bearing rabbit or human GHR. Notably, this antibody has little effect on GH binding and also inhibits inducible metalloproteolysis of the GHR that occurs in the perimembranous ECD stem region. In the current study, we demonstrate that anti-GHR(ext-mAb) inhibits GH-dependent cellular proliferation and also inhibits hepatic GH signaling in vivo in mice that adenovirally express rabbit GHR, as assessed with our noninvasive bioluminescence hepatic signaling assay. A separate monoclonal antibody (anti-GHR(mAb 18.24)) is a sister clone of anti-GHR(ext-mAb). Here, we demonstrate that anti-GHR(mAb 18.24) also inhibits rabbit and human GHR signaling and inducible receptor proteolysis. Further, we use a random PCR-generated mutagenic expression system to map the three-dimensional epitopes in the rabbit GHR ECD for both anti-GHR(ext-mAb) and anti-GHR(mAb 18.24). We find that each of the two antibodies has similar, but nonidentical, discontinuous epitopes that include regions of subdomain 2 encompassing the dimerization interface. These results have fundamental implications for understanding the role of the dimerization interface and subdomain 2 in GHR activation and regulated GHR metalloproteolysis and may inform development of therapeutics that target GHR.

Measures of pulsatile GH secretion require frequent collection and analysis of blood samples at regular intervals. Due to blood volume constraints, repeat measures of circulating levels of GH in mice remain challenging. Consequently, few observations exist in which the pulsatile pattern of GH secretion in mice have been characterized. To address this, we developed a technique for the collection and analysis of circulating levels of GH at regular and frequent intervals in freely moving mice. This was achieved through the development of a sensitive assay for the detection of GH in small (2 μl) quantities of whole blood. The specificity and accuracy of this assay was validated following guidelines established for single-laboratory validation as specified by the International Union of Pure and Applied Chemistry. We incorporated an established method for tail-clip blood sample collection to determine circulating levels of GH secretion in 36 whole blood samples collected consecutively over a period of 6 h. Resulting measures were characterized by peak secretion periods and interpulse stable baseline secretion periods. Periods characterized by elevated whole blood GH levels consisted of multicomponent peaks. Deconvolution analysis of resulting measures confirmed key parameters associated with pulsatile GH secretion. We show a striking decrease in pulsatile GH secretion in mice after 12-18 h of fasting. This model is necessary to characterize the pulsatile profile of GH secretion in mice and will significantly contribute to current attempts to clarify mechanisms that contribute to the regulation of GH secretion.

GH deficiency is known to be clinically associated with a high incidence of nonalcoholic fatty liver disease, and this can be reversed by GH administration. Here we investigated the mechanistic basis for this phenomenon using engineered male mice lacking different signaling elements of the GH receptor, hepatic stat5a/b−/− mice and a mouse hepatoma line. We found deficient GH-dependent signal transducer and activator of transcription (STAT)-5 signaling correlates with steatosis, and through microarray analysis, quantitative PCR, and chromatin immunoprecipitation, identified putative targets of STAT5 signaling responsible for the steatosis seen on a normal diet. These targets were verified with liver-specific stat5a/b deletion in vivo, and in vitro we show that dominant-negative (DN) STAT5 increases lipid uptake in a mouse hepatoma line. Because loss of STAT5 signaling results in elevated STAT1 and STAT3 activity and intracellular lipid accumulation, we have used DN-STAT5a/b, DN-STAT1, constitutively active (CA)-STAT3, or addition of oleate/palmitate in the hepatoma line to assign which of these apply to individual targets in STAT5 signaling deficiency. These findings and published mouse models of steatosis enable us to propose elevated cd36, pparγ, and pgc1α/β expression as primary instigators of the steatosis along with elevated fatty acid synthase, lipoprotein lipase, and very low-density lipoprotein receptor expression. Decreased fgf21 and insig2 expression may also contribute. In conclusion, despite normal plasma free fatty acids and minimal obesity, absent GH activation leads to steatosis because activated STAT5 prevents hepatic steatosis. These results raise the possibility of low-dose GH treatment for nonalcoholic fatty liver disease.

Background: The growth hormone receptor (GHR) was the first class 1 cytokine receptor to be cloned, and it has been studied intensively. The crystal structures of the bound and unbound forms have been solved and the energetic contributions of residues involved in the binding interaction have been quantified. Two receptor subunits bind to opposite sides of the hormone through site 1 and site 2, and a third interaction occurs between receptors in the lower β-sandwich module at site 3. All three interactions are required for receptor activation, which was thought to be a consequence of hormone-induced receptor dimerization. However, substantial data support the existence of a constitutive receptor dimer that interacts via the transmembrane domain (TMD), with receptor activation triggered by a hormone-induced conformational change. Mutagenesis studies and crystal structure data indicate that receptor activation involves a relative rotation and scissor movement of subunits to activate the associated tyrosine kinase, Janus kinase 2 (JAK2). We have recently reported that a second tyrosine kinase, an Src-family kinase, also associates constitutively with the receptor and activates the Ras–extracellular-signal-regulated kinase pathway. Activation of this kinase requires a conformational change in a loop of the lower sandwich module, and a different orientation of the TMDs than needed for JAK2 activation. Conclusions: This structural difference could allow differential activation of these two kinases by GH analogues such as I179M human GH.