The Effects of Neuropeptide Y Overexpression on the Mouse Model of Doxorubicin-Induced Cardiotoxicity

Doxorubicin is a potent anticancer drug with cardiotoxicity hampering its use. Neuropeptide Y (NPY) is the most abundant neuropeptide in the heart and a co-transmitter of the sympathetic nervous system that plays a role in cardiac diseases. The aim of this work was to study the impact of NPY on doxorubicin-induced cardiotoxicity. Transgenic mice overexpressing NPY in noradrenergic neurons (NPY-OEDβH) and wild-type mice were treated with a single dose of doxorubicin. Doxorubicin caused cardiotoxicity in both genotypes as demonstrated by decreased weight gain, tendency to reduced ejection fraction, and changes in the expression of several genes relevant to cardiac pathology. Doxorubicin resulted in a tendency to lower ejection fraction in NPY-OEDβH mice more than in wild-type mice. In addition, gain in the whole body lean mass gain was decreased only in NPY-OEDβH mice, suggesting a more severe impact of doxorubicin in this genotype. The effects of doxorubicin on genes expressed in the heart were similar between NPY-OEDβH and wild-type mice. The results demonstrate that doxorubicin at a relatively low dose caused significant cardiotoxicity. There were differences between NPY-OEDβH and wild-type mice in their responses to doxorubicin that suggest NPY to increase susceptibility to cardiotoxicity. This may point to the therapeutic implications as suggested for NPY system in other cardiovascular diseases.</p

Diet-induced obesity in mice overexpressing neuropeptide y in noradrenergic neurons

Neuropeptide Y (NPY) is a neurotransmitter associated with feeding and obesity. We have constructed an NPY transgenic mouse model (OE- mouse), where targeted overexpression leads to increased levels of NPY in noradrenergic and adrenergic neurons. We previously showed that these mice become obese on a normal chow. Now we aimed to study the effect of a Western-type diet in OE- and wildtype (WT) mice, and to compare the genotype differences in the development of obesity, insulin resistance, and diabetes. Weight gain, glucose, and insulin tolerance tests, fasted plasma insulin, and cholesterol levels were assayed. We found that female OE- mice gained significantly more weight without hyperphagia or decreased activity, and showed larger white and brown fat depots with no difference in UCP-1 levels. They also displayed impaired glucose tolerance and decreased insulin sensitivity. OE- and WT males gained weight robustly, but no difference in the degree of adiposity was observed. However, 40% of but none of the WT males developed hyperglycaemia while on the diet. The present study shows that female OE- mice were not protected from the obesogenic effect of the diet suggesting that increased NPY release may predispose females to a greater risk of weight gain under high caloric conditions.</p

Treatment with Soluble Activin Type IIB Receptor Ameliorates Ovariectomy-Induced Bone Loss and Fat Gain in Mice

Introduction In postmenopausal osteoporosis, hormonal changes lead to increased bone turnover and metabolic alterations including increased fat mass and insulin resistance. Activin type IIB receptors bind several growth factors of the TGF-beta superfamily and have been demonstrated to increase muscle and bone mass. We hypothesized that ActRIIB-Fc treatment could improve bone and muscle mass, inhibit fat accumulation, and restore metabolic alterations in an ovariectomy (OVX) model of postmenopausal osteoporosis. Materials and Methods Female C57Bl/6 N mice were subjected to SHAM or OVX procedures and received intraperitoneal injections of either PBS or ActRIIB-Fc (5 mg/kg) once weekly for 7 weeks. Glucose and insulin tolerance tests (GTT and ITT, respectively) were performed at 7 and 8 weeks, respectively. Bone samples were analyzed with micro-computed tomography imaging, histomorphometry, and quantitative RT-PCR. Results Bone mass decreased in OVX PBS mice compared to the SHAM PBS group but ActRIIB-Fc was able to prevent these changes as shown by mu CT and histological analyses. This was due to decreased osteoclast numbers and function demonstrated by histomorphometric and qRT-PCR analyses. OVX induced adipocyte hypertrophy that was rescued by ActRIIB-Fc, which also decreased systemic adipose tissue accumulation. OVX itself did not affect glucose levels in GTT but ActRIIB-Fc treatment resulted in impaired glucose clearance in both SHAM and OVX groups. OVX induced mild insulin resistance in ITT but ActRIIB-Fc treatment did not affect this. Conclusion Our results reinforce the potency of ActRIIB-Fc as a bone-enhancing agent but also bring new insight into the metabolic effects of ActRIIB-Fc in normal and OVX mice.Peer reviewe

Lihavuusleikkauksen vaikutukset lääkkeiden farmakokinetiikkaan

Lihavuusleikkaus muuttaa ruoansulatuselimistön anatomiaa ja potilaan kehon koostumusta, mikä vaikuttaa lääkkeiden farmakokinetiikkaan. Leikkauksen välittömiä seurauksia ovat lääkkeiden imeytymisen ja ensikierron aineenvaihdunnan muutokset. Lääkkeen jakautumistilavuus, aineenvaihdunta ja eliminaatio saattavat muuttua rasvakudoksen ja maksan rasvoittumisen vähenemisen sekä munuaistoiminnan parantumisen myötä. Lääkepitoisuuksien suurentuminen tai pienentyminen voivat vaikuttaa lääkehoidon tehoon ja haittavaikutusriskiin. Yksittäisten lääkkeiden osalta näyttö on puutteellista, eikä selkeitä yleissuosituksia lääkkeiden lihavuusleikkauksen jälkeisistä annoksista ole saatavilla. Leikkaustekniikka ja yksilölliset potilaskohtaiset tekijät vaikuttavat farmakokinetiikan muutoksiin. Muutosten vaikean ennakoitavuuden takia on tärkeää seurata lääkehoidon kliinistä vastetta, haittavaikutuksia ja tarvittaessa lääkepitoisuuksia 1-2 vuoden ajan leikkauksesta, jolloin paino vähenee eniten

MMP-13 Regulates Growth of Wound Granulation Tissue and Modulates Gene Expression Signatures Involved in Inflammation, Proteolysis, and Cell Viability

Proteinases play a pivotal role in wound healing by regulating cell-matrix interactions and availability of bioactive molecules. The role of matrix metalloproteinase-13 (MMP-13) in granulation tissue growth was studied in subcutaneously implanted viscose cellulose sponge in MMP-13 knockout (Mmp13−/−) and wild type (WT) mice. The tissue samples were harvested at time points day 7, 14 and 21 and subjected to histological analysis and gene expression profiling. Granulation tissue growth was significantly reduced (42%) at day 21 in Mmp13−/− mice. Granulation tissue in Mmp13−/− mice showed delayed organization of myofibroblasts, increased microvascular density at day 14, and virtual absence of large vessels at day 21. Gene expression profiling identified differentially expressed genes in Mmp13−/− mouse granulation tissue involved in biological functions including inflammatory response, angiogenesis, cellular movement, cellular growth and proliferation and proteolysis. Among genes linked to angiogenesis, Adamts4 and Npy were significantly upregulated in early granulation tissue in Mmp13−/− mice, and a set of genes involved in leukocyte motility including Il6 were systematically downregulated at day 14. The expression of Pdgfd was downregulated in Mmp13−/− granulation tissue in all time points. The expression of matrix metalloproteinases Mmp2, Mmp3, Mmp9 was also significantly downregulated in granulation tissue of Mmp13−/− mice compared to WT mice. Mmp13−/− mouse skin fibroblasts displayed altered cell morphology and impaired ability to contract collagen gel and decreased production of MMP-2. These results provide evidence for an important role for MMP-13 in wound healing by coordinating cellular activities important in the growth and maturation of granulation tissue, including myofibroblast function, inflammation, angiogenesis, and proteolysis

Treatment with Soluble Activin Type IIB Receptor Ameliorates Ovariectomy-Induced Bone Loss and Fat Gain in Mice

IntroductionIn postmenopausal osteoporosis, hormonal changes lead to increased bone turnover and metabolic alterations including increased fat mass and insulin resistance. Activin type IIB receptors bind several growth factors of the TGF-beta superfamily and have been demonstrated to increase muscle and bone mass. We hypothesized that ActRIIB-Fc treatment could improve bone and muscle mass, inhibit fat accumulation, and restore metabolic alterations in an ovariectomy (OVX) model of postmenopausal osteoporosis.Materials and MethodsFemale C57Bl/6 N mice were subjected to SHAM or OVX procedures and received intraperitoneal injections of either PBS or ActRIIB-Fc (5 mg/kg) once weekly for 7 weeks. Glucose and insulin tolerance tests (GTT and ITT, respectively) were performed at 7 and 8 weeks, respectively. Bone samples were analyzed with micro-computed tomography imaging, histomorphometry, and quantitative RT-PCR.ResultsBone mass decreased in OVX PBS mice compared to the SHAM PBS group but ActRIIB-Fc was able to prevent these changes as shown by mu CT and histological analyses. This was due to decreased osteoclast numbers and function demonstrated by histomorphometric and qRT-PCR analyses. OVX induced adipocyte hypertrophy that was rescued by ActRIIB-Fc, which also decreased systemic adipose tissue accumulation. OVX itself did not affect glucose levels in GTT but ActRIIB-Fc treatment resulted in impaired glucose clearance in both SHAM and OVX groups. OVX induced mild insulin resistance in ITT but ActRIIB-Fc treatment did not affect this.ConclusionOur results reinforce the potency of ActRIIB-Fc as a bone-enhancing agent but also bring new insight into the metabolic effects of ActRIIB-Fc in normal and OVX mice.</p

Single-Cell Proteomics Reveals the Defined Heterogeneity of Resident Macrophages in White Adipose Tissue

Adipose tissue macrophages (ATMs) regulate homeostasis and contribute to the metabolically harmful chronic inflammation in obese individuals. While evident heterogeneity of resident ATMs has been described previously, their phenotype, developmental origin, and functionality remain inconsistent. We analyzed white adipose tissue (WAT) during homeostasis and diet interventions using comprehensive and unbiased single-cell mass cytometry and genetic lineage tracking models. We now provide a uniform definition of individual subsets of resident ATMs. We show that in lean mice, WAT co-harbors eight kinetically evolving CD206+ macrophage subpopulations (defined by TIM4, CD163, and MHC II) and two CD206- macrophage subpopulations. TIM4-CD163+, TIM4-CD163- and CD206- macrophage populations are largely bone marrow-derived, while the proliferating TIM4+CD163+ subpopulation is of embryonic origin. All macrophage subtypes are active in phagocytosis, endocytosis, and antigen processing in vitro, whereas TIM4+CD163+ cells are superior in scavenging in vivo. A high-fat diet induces massive infiltration of CD206- macrophages and selective down-regulation of MHC II on TIM4+ macrophages. These changes are reversed by dietary intervention. Thus, the developmental origin and environment jointly regulate the functional malleability of resident ATMs.</p

Peripherally Administered Y-2-Receptor Antagonist BIIE0246 Prevents Diet-Induced Obesity in Mice With Excess Neuropeptide Y, but Enhances Obesity in Control Mice

Neuropeptide Y (NPY) plays an important role in the regulation of energy homeostasis in the level of central and sympathetic nervous systems (SNSs). Genetic silencing of peripheral Y-2-receptors have anti-obesity effects, but it is not known whether pharmacological blocking of peripheral Y-2-receptors would similarly benefit energy homeostasis. The effects of a peripherally administered Y-2-receptor antagonist were studied in healthy and energy-rich conditions with or without excess NPY. Genetically obese mice overexpressing NPY in brain noradrenergic nerves and SNS (OE-NPYD beta H) represented the situation of elevated NPY levels, while wildtype (WT) mice represented the normal NPY levels. Specific Y-2-receptor antagonist, BIIE0246, was administered (1.3 mg/kg/day, i.p.) for 2 or 4.5 weeks to OE-NPYD beta H and WT mice feeding on chow or Western diet. Treatment with Y-2-receptor antagonist increased body weight gain in both genotypes on chow diet and caused metabolic disturbances (e.g., hyperinsulinemia and hypercholesterolemia), especially in WT mice. During energy surplus (i.e., on Western diet), blocking of Y-2-receptors induced obesity in WT mice, whereas OE-NPYD beta H mice showed reduced fat mass gain, hepatic glycogen and serum cholesterol levels relative to body adiposity. Thus, it can be concluded that with normal NPY levels, peripheral Y-2-receptor antagonist has no potential for treating obesity, but oppositely may even induce metabolic disorders. However, when energy-rich diet is combined with elevated NPY levels, e.g., stress combined with an unhealthy diet, Y-2-receptor antagonism has beneficial effects on metabolic status

Seasonal variation in the brain μ-opioid receptor availability

Seasonal rhythms influence emotion and sociability. The brain μ-opioid receptor (MOR) system modulates a multitude of seasonally varying socioemotional functions, but its seasonal variation remains elusive with no previously reported in vivo evidence. Here, we first conducted a cross-sectional study with previously acquired human [11C]carfentanil PET imaging data (132 male and 72 female healthy subjects) to test whether there was seasonal difference in MOR availability. We then investigated experimentally whether seasonal variation in daylength causally influences brain MOR availability in rats. Rats (six male and three female rats) underwent daylength cycle simulating seasonal changes; control animals (two male and one female rats) were kept under constant daylength. Animals were scanned repeatedly with [11C]carfentanil PET imaging. Seasonally varying daylength had an inverted U-shaped functional relationship with brain MOR availability in humans. Brain regions sensitive to daylength spanned the socio-emotional brain circuits, where MOR availability formed a spring-like peak. In rats, MOR availabilities in the brain neocortex, thalamus and striatum peaked at intermediate daylength. Varying daylength also affected the weight gain and stress hormone. We conclude that the in vivo brain MOR availability in humans and rats shows significant seasonal variation, which is predominately associated with seasonal photoperiodic variation. Given the intimate links between MOR signaling and socioemotional behavior, these results suggest that the MOR system might underlie seasonal variation in human mood and social behavior.</p

Vimentin regulates Notch signaling strength and arterial remodeling in response to hemodynamic stress

The intermediate filament (IF) cytoskeleton has been proposed to regulate morphogenic processes by integrating the cell fate signaling machinery with mechanical cues. Signaling between endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) through the Notch pathway regulates arterial remodeling in response to changes in blood flow. Here we show that the IF-protein vimentin regulates Notch signaling strength and arterial remodeling in response to hemodynamic forces. Vimentin is important for Notch transactivation by ECs and vimentin knockout mice (VimKO) display disrupted VSMC differentiation and adverse remodeling in aortic explants and in vivo. Shear stress increases Jagged1 levels and Notch activation in a vimentin-dependent manner. Shear stress induces phosphorylation of vimentin at serine 38 and phosphorylated vimentin interacts with Jagged1 and increases Notch activation potential. Reduced Jagged1-Notch transactivation strength disrupts lateral signal induction through the arterial wall leading to adverse remodeling. Taken together we demonstrate that vimentin forms a central part of a mechanochemical transduction pathway that regulates multilayer communication and structural homeostasis of the arterial wall