Female Tg Research Articles

Differential autophagy power in the spinal cord and muscle of transgenic ALS mice

Amyotrophic lateral sclerosis (ALS) is a motoneuron disease characterized by misfolded proteins aggregation in affected motoneurons. In mutant SOD1 (mutSOD1) ALS models, aggregation correlates to impaired functions of proteasome and/or autophagy, both essential for the intracellular chaperone-mediated protein quality control (PQC), and to a reduced mutSOD1 clearance from motoneurons. Skeletal muscle cells are also sensitive to mutSOD1 toxicity, but no mutSOD1 aggregates are formed in these cells, that might better manage mutSOD1 than motoneurons. Thus, we analyzed in spinal cord and in muscle of transgenic (tg) G93A-SOD1 mice at presymptomatic (PS, 8 weeks) and symptomatic (S, 16 weeks) stages, and in age-matched control mice, whether mutSOD1 differentially modulates relevant PQC players, such as HSPB8, BAG3, and BAG1. Possible sex differences were also considered. No changes of HSPB8, BAG3, and BAG1 at PS stage (8 weeks) were seen in all tissues examined in tg G93A-SOD1 and control mice. At S stage (16 weeks), HSPB8 dramatically increased in skeletal muscle of tg G93A-SOD1 mice, while a minor increase occurred in spinal cord of male, but not female tg G93A-SOD1 mice. BAG3 expression increased both in muscle and spinal cord of tg G93A-SOD1 mice at S stage, BAG1 expression increased only in muscle of the same mice. Since, HSPB8-BAG3 complex assists mutSOD1 autophagic removal, we analyzed two well-known autophagic markers, LC3 and p62. Both LC3 and p62 mRNAs were significantly up-regulated in skeletal muscle of tg G93A-SOD1 mice at S stage (16 weeks). This suggests that mutSOD1 expression induces a robust autophagic response specifically in muscle. Together these results demonstrate that, in muscle mutSOD1-induced autophagic response is much higher than in spinal cord. In addition, if mutSOD1 exerts toxicity in muscle, this may not be mediated by misfolded proteins accumulation. It remains unclear whether in muscle mutSOD1 toxicity is related to aberrant autophagy activation.

Thioredoxin 1 Overexpression Extends Mainly the Earlier Part of Life Span in Mice

We examined the effects of increased levels of thioredoxin 1 (Trx1) on resistance to oxidative stress and aging in transgenic mice overexpressing Trx1 [Tg(TRX1)(+/0)]. The Tg(TRX1)(+/0) mice showed significantly higher Trx1 protein levels in all the tissues examined compared with the wild-type littermates. Oxidative damage to proteins and levels of lipid peroxidation were significantly lower in the livers of Tg(TRX1)(+/0) mice compared with wild-type littermates. The survival study demonstrated that male Tg(TRX1)(+/0) mice significantly extended the earlier part of life span compared with wild-type littermates, but no significant life extension was observed in females. Neither male nor female Tg(TRX1)(+/0) mice showed changes in maximum life span. Our findings suggested that the increased levels of Trx1 in the Tg(TRX1)(+/0) mice were correlated to increased resistance to oxidative stress, which could be beneficial in the earlier part of life span but not the maximum life span in the C57BL/6 mice.

Subcellular effects of myocyte-specific androgen receptor overexpression in mice

Although androgen receptor (AR) within myocytes is thought to mediate many of the effects of testosterone and other androgens on skeletal muscle, little is known about the functions of AR within these cells. We, therefore, studied the ultrastructure of skeletal muscle of HSA-AR transgenic (Tg) mice that overexpress AR selectively in myocytes and exhibit neuromuscular atrophy. We examined male HSA-AR mice from two different founding lines: L78 (lower copy number and less severe phenotype) and L141 (higher copy number and more severe phenotype) and compared these to wild-type (Wt) brothers. We also examined testosterone-treated female mice from these two lines and compared them both to their Wt sisters and to vehicle-treated controls. Ultrastructural examination of extensor digitorum longus sections using transmission electron microscopy revealed remarkably disorganized myofibrils in male Tg and testosterone-treated female Tg mice. Quantification of ultrastructural pathology indicated reduced myofibril width, hypertrophic and hyperplastic intermyofibrillar mitochondria, and pronounced glycogen accumulation in HSA-AR males of both lines. Reduced myofibrillar width and increases in mitochondrial number, size, and volume density were also observed in testosterone-treated HSA-AR females, although glycogen accumulation was not observed. Structural abnormalities in mitochondria were also associated with increases in electron transport chain activity and systemic resting metabolic rate, indicative of hypermetabolism. We find that overexpression of AR in myocytes of HSA-AR mice results in alterations in myofibrils, mitochondria, and glycogen. Alterations in myofibrils and mitochondria appear to result from acute actions of testosterone, whereas those on glycogen do not. Pathology of myofibrils and/or mitochondria may, therefore, mediate in part the neuromuscular atrophy observed in HSA-AR mice.

Metal Ionophore Treatment Restores Dendritic Spine Density and Synaptic Protein Levels in a Mouse Model of Alzheimer's Disease

We have previously demonstrated that brief treatment of APP transgenic mice with metal ionophores (PBT2, Prana Biotechnology) rapidly and markedly improves learning and memory. To understand the potential mechanisms of action underlying this phenomenon we examined hippocampal dendritic spine density, and the levels of key proteins involved in learning and memory, in young (4 months) and old (14 months) female Tg2576 mice following brief (11 days) oral treatment with PBT2 (30 mg/kg/d). Transgenic mice exhibited deficits in spine density compared to littermate controls that were significantly rescued by PBT2 treatment in both the young (+17%, p<0.001) and old (+32%, p<0.001) animals. There was no effect of PBT2 on spine density in the control animals. In the transgenic animals, PBT2 treatment also resulted in significant increases in brain levels of CamKII (+57%, p = 0.005), spinophilin (+37%, p = 0.04), NMDAR1A (+126%, p = 0.02), NMDAR2A (+70%, p = 0.05), pro-BDNF (+19%, p = 0.02) and BDNF (+19%, p = 0.04). While PBT2-treatment did not significantly alter neurite-length in vivo, it did increase neurite outgrowth (+200%, p = 0.006) in cultured cells, and this was abolished by co-incubation with the transition metal chelator, diamsar. These data suggest that PBT2 may affect multiple aspects of snaptic health/efficacy. In Alzheimer's disease therefore, PBT2 may restore the uptake of physiological metal ions trapped within extracellular β-amyloid aggregates that then induce biochemical and anatomical changes to improve cognitive function.

Chronic cerebral hypoperfusion in a mouse model of Alzheimer's disease: An additional contributing factor of cognitive impairment

The purpose of the present study was to evaluate whether chronic cerebral hypoperfusion would affect cognitive status in an Alzheimer mouse model. Behavioral tests and histological evaluations were performed using female Tg2576 mice eight weeks after right common carotid artery occlusion (rCCAO), which is known to induce a type of vascular dementia without neuronal necrosis in nontransgenic mice. Positron emission tomography with 18F-fluorodeoxyglucose (FDG-PET) was utilized to evaluate metabolic status in the rCCAO-operated brain of nontransgenic mice. Escape latency from the Morris water maze test was not significantly different between rCCAO- and sham-operated mice. However, the learning curve was impaired in rCCAO-operated transgenic mice while it was preserved in sham-operated transgenic or rCCAO-operated nontransgenic mice. Histological examination revealed no evidence of cell death in the rCCAO-operated brains, and the extent of amyloid deposition was not different in rCCAO- and sham-operated mice. The brain of rCCAO-operated mice showed metabolic deficits in the ipsilateral parietal cortex through FDG-PET. In conclusion, further cognitive decline which is more comparable to typical Alzheimer's disease was induced by chronic cerebral hypoperfusion in an Alzheimer mouse model. This aggravation might be associated with hypometabolism via chronic cerebral hypoperfusion.

Influence of partial agonist expression on CD8 T cell responses for non-self antigens (132.35)

Abstract Differences in affinity of TCR for peptide/MHC complex induced by single amino acid substitutions in the peptide dramatically alter recognition by T cell in the periphery. With H60 as an antigenic model, we investigated the influence of transgenic expression of natural H60 antigen (H60N Tg) or of H60 antigen with single amino acid substitution at position 4 to histidine (H60H Tg) on H60H- or H60N-specific CD8 T cell responses, respectively. Immunization of B6 female mice with splenocytes from male H60NTg or H60H Tg mice induced strong CD8 T cell responses against each epitope, H60N or H60H, in CD4 T cell help dependent ways. While the immunization with splenocytes from male H60H Tg induced proliferation of H60-specific CD8 T cell responses in the female H60N Tg mice, CD8 T cell response for H60H induced in female H60N Tg showed significant reduction in the magnitude of H60H-tetramer-binding CD8 T cells at the peak time. And differences in TCR V beta usages of H60H-reactive CD8 T cells were also found between in the female B6 female and female H60N Tg hosts. Our data suggest that expression of proteins with amino acid changes influences the antigen-specific CD8 T cell responses and repertoire of TCRS involved in the responses.

DHA diet reduces AD pathology in young APPswe/PS1ΔE9 transgenic mice: Possible gender effects

Epidemiological and clinical trial findings suggest that consumption of docosahexaenoic acid (DHA) lowers the risk of Alzheimer's disease (AD). We examined the effects of short-term (3 months) DHA enriched diet on plaque deposition and synaptic defects in forebrain of young APPswe/PS1 Delta E9 transgenic (tg) and non-transgenic (ntg) mice. Gas chromatography revealed a significant increase in DHA concomitant with a decrease of arachidonic acid in both brain and liver in mice fed with DHA. Female tg mice consumed relatively more food daily than ntg female mice, independent of diet. Plaque load was significantly reduced in the cortex, ventral hippocampus and striatum of female APPswe/PS1 Delta E9 tg mice on DHA diet compared to female tg mice on control diet. Immunoblot quantitation of the APOE receptor, LR11, which is involved in APP trafficking and A beta production, were unchanged in mice on DHA or control diets. Moreover drebrin levels were significantly increased in the hippocampus of tg mice on the DHA diet. Finally, in vitro DHA treatment prevented amyloid toxicity in cell cultures. Our findings support the concept that increased DHA consumption may play and important role in reducing brain insults in female AD patients.

PND37 ANTIPSYCHOTIC DRUG USE IN PATIENTS WITH ALZHEIMER'S DISEASE TREATED WITH RIVASTIGMINE VERSUS DONEPEZIL: EVIDENCE FROM HEALTH CLAIMS DATA

(SAD) were used for studies on mechanism of PN401 action. Results: Female APPswe P301L (TAPP) mice that began PN401 treatment at 5 months of age had improved social transmission of food preference at 7 and 12 months. PN401 treatment also improved novel object recognition at 7 and 13 months of age. TAPP mice given PN401 treatment improved motor learning on the accelerated rotarod as compared to TAPP control mice. PN401 given for two months starting at 4 months of age in female Tg2576 APPswe mice improved contextual fear memory that was impaired in 6-month old Tg2576 control mice. Further biochemical and histological analysis of these mice is underway. The mechanism for the improvement in memory in the mouse models of AD due to PN401 may include reduced oxidative stress evident by a reduction in urinary isoprostane F2 . Studies in SH-SY5Y cells indicate that uridine can increase sAPP secretion, enhance neurite outgrowth and reduce ROS formation. Uridine (20-200 M) was also shown to protect fibroblasts from AD patients in a chemical hypoxia model. Conclusions: PN401 is an oral drug that may be beneficial in treatment of multiple etiological factors associated with AD.

Astroglial-NF-kB is a critical regulator of learning and memory and hippocampal neurogenesis in female mice

Event Abstract Back to Event Astroglial-NF-kB is a critical regulator of learning and memory and hippocampal neurogenesis in female mice John Bethea1*, Valerie Bracchi-Ricard1, Giorgia Quadrato1, 2, Anna Dellarole1, 2 and Mariagrazia Grilli2 1 University of Miami, United States 2 University of Piemonte Orientale, Italy We previously investigated the role of astroglial-NF-kB in synaptic plasticity and learning and memory using transgenic mice overexpressing a dominant negative form of IkBa in astrocytes (GFAP-IkBa-dn). We found that female transgenic mice (TG), but not males, have robust deficits in hippocampal and extra-hippocampal-dependent learning and memory. These findings indicate that astroglial NF-kB is an important regulator of learning/memory. These results suggest that neurogenesis may be affected in our female mice.Active neurogenesis continues in the hippocampus throughout adulthood, due to the presence of progenitor cells localized in the subgranular zone of the dentate gyrus (DG). In the hippocampus new neurons become part of an integrated network that plays an important role in learning and memory. Since GFAP is expressed by both putative stem cells and astrocytes in the neurogenic niches, we investigated the contribution of the NF-kB family of transcription factors in adult hippocampal neurogenesis by studying proliferation, survival and differentiation of hippocampal precursor cells in male and female TG mice. Herein, we demonstrate that there are no differences in the proliferation of neuronal stem/progenitor cells in male and female wild type (WT) and TG. The survival and differentiation of neuronal stem/progenitor cells in male TG was also unchanged compared to male WT mice. However, there was a significant reduction in the survival and differentiation of neuronal stem/progenitor cells in female TG mice compared to WT female controls. These results may help explain our sex specific deficits in learning and memory. Since deficits in neuronal stem cells and learning and memory may also be associated with major depressive disorders and stress, which women are reported to suffer from 2-3 times more frequently than men these results may link astroglial-NF-kB to mechanisms underlying major depressive disorders and other sex specific disorders in women. Conference: 41st European Brain and Behaviour Society Meeting, Rhodes Island, Greece, 13 Sep - 18 Sep, 2009. Presentation Type: Oral Presentation Topic: Symposia lectures Citation: Bethea J, Bracchi-Ricard V, Quadrato G, Dellarole A and Grilli M (2009). Astroglial-NF-kB is a critical regulator of learning and memory and hippocampal neurogenesis in female mice. Conference Abstract: 41st European Brain and Behaviour Society Meeting. doi: 10.3389/conf.neuro.08.2009.09.013 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 04 Jun 2009; Published Online: 04 Jun 2009. * Correspondence: John Bethea, University of Miami, Miami, United States, jbethea@miami.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers John Bethea Valerie Bracchi-Ricard Giorgia Quadrato Anna Dellarole Mariagrazia Grilli Google John Bethea Valerie Bracchi-Ricard Giorgia Quadrato Anna Dellarole Mariagrazia Grilli Google Scholar John Bethea Valerie Bracchi-Ricard Giorgia Quadrato Anna Dellarole Mariagrazia Grilli PubMed John Bethea Valerie Bracchi-Ricard Giorgia Quadrato Anna Dellarole Mariagrazia Grilli Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Aluminum exposure through the diet: Metal levels in AβPP transgenic mice, a model for Alzheimer's disease

Aluminum (Al), iron (Fe), copper (Cu), and zinc (Zn) cause have been implicated in the etiology of certain neurodegenerative disorders. Moreover, these elements cause the conformational changes of Alzheimer's amyloid β protein. In this study, we determined the concentrations of Al, Cu, Zn, Fe, and Mn in various tissues of Tg 2576 (AβPP transgenic) Al-treated mice. Female Tg 2576 mice and wild-type littermates were exposed through the diet to 1 mg Al/g for 6 months. At 11 months of age, metal concentrations were measured in various tissues. In brain, Al levels were higher in hippocampus than in cortex and cerebellum. In hippocampus, Cu concentrations decreased in non-treated Tg 2576 mice, while Zn levels were higher in Al-treated mice. Copper, Zn, Mn and Fe concentrations in liver, kidney and bone were not affected by Al exposure. The current results show that Al exposure of Tg 2576 and wild-type mice did not produce important metal changes related with the genotype, responding similarly both groups of animals. As Tg 2576 mice have been considered as a potential model for Alzheimer's disease (AD), the present results would not support the hypothetical role of Al in the etiology of AD.

Neurofurans, Novel Indices of Oxidant Stress Derived from Docosahexaenoic Acid

Isoeicosanoids are free radical-catalyzed isomers of the enzymatic products of arachidonic acid. They are formed in situ in cell membranes, are cleaved, circulate, and are excreted in urine. Isomers of prostaglandin F(2alpha), the F(2)-isoprostanes, have emerged as sensitive indices of lipid peroxidation in vivo. Analogous compounds formed from docosahexaenoic acid (DHA) are termed neuroprostanes and are more abundant than isoprostanes (iPs) in brain. Isofurans are another class of isoeicosanoids characterized by a substituted tetrahydrofuran ring. They are preferentially formed, relative to iPs, under conditions of elevated oxygen tension. Here, we report the discovery of neurofurans (nFs), the analogous family of compounds formed from DHA. Formation of nFs is characterized by mass spectrometry and confirmed by oxidation of DHA in vitro and following CCl(4) administration in liver in vivo. It is demonstrated that the levels of nFs are elevated in the brain cortex of a mouse model of Alzheimer disease and are depressed in mouse brain cortex by deletion of p47(phox), an essential component of the phagocyte NADPH oxidase. Measurement of the nFs may ultimately prove useful in diagnosis, timing, and selection of dose in the treatment and chemoprevention of neurodegenerative disease.

Gender Difference in ICER Iγ Transgenic Diabetic Mouse

Few studies have been done to examine gender differences in diabetic mouse models. Here we examined a gender difference in Inducible cAMP Early Repressor (ICER) transgenic (Tg) mice, a diabetic mouse model. Longitudinal changes in diabetes and nephropathy were investigated in male and female Tg mice. Both male and female Tg mice developed severe diabetes early in life due to severely impaired insulin synthesis and decreased beta-cell numbers, but only female Tg mice became less hyperglycemic later in life, and most female Tg mice did not develop diabetic nephropathy. Even some female Tg mice that remained hyperglycemic showed less renal expansion than age-matched male Tg mice. Thus the gender difference in the severity of diabetes and diabetic nephropathy was evident with age in this model. This study indicates that sex hormones may play a role in glucose metabolism in diabetic conditions.

Catalase overexpression attenuates angiotensinogen expression and apoptosis in diabetic mice

Increased generation of reactive oxygen species (ROS) leads to oxidative stress in diabetes. Catalase is a highly conserved heme-containing protein that reduces hydrogen peroxide to water and oxygen and is an important factor decreasing cellular injury owing to oxidative stress. Hyperglycemic conditions increase oxidative stress and angiotensinogen gene expression. Angiotensinogen conversion to angiotensin II leads to a furtherance in oxidative stress through increased generation of reactive oxygen species. In this study, we utilized mice transgenically overexpressing rat catalase in a kidney-specific manner to determine the impact on ROS, angiotensinogen and apoptotic gene expression in proximal tubule cells of diabetic animals. Proximal tubules isolated from wild-type and transgenic animals without or with streptozotocin-induced diabetes were incubated in low glucose media in the absence or presence of angiotensin II or in a high-glucose media. Our results show that the overexpression of catalase prevents the stimulation of ROS and angiotensinogen mRNA in tubules owing to elevated glucose or angiotensin II in vitro. Additionally, overexpression of catalase attenuated ROS generation, angiotensinogen and proapoptotic gene expression and apoptosis in the kidneys of diabetic mice in vivo. Our studies point to an important role of ROS in the pathophysiology of diabetic nephropathy.

The Impact of B Lymphocyte Depletion on the Pathogenesis of Autoimmune Diabetes (131.28)

Abstract NOD B cell development is characterized by a defective homeostatic checkpoint in B cell maturation and selection. Having demonstrated that the progression of autoimmune diabetes requires antigen presentation by B-lymphocytes, we hypothesized that B cell depletion may prevent diabetes progression in NOD mice. Here, we employed two distinct approaches for in vivo B lymphocyte depletion: a cohort of adult hCD20 Tg NOD mice were treated with the B lymphocyte depleting mAb, Rituximab (anti-CD20) anda cohort of adult NOD mice were treated with a neutralizing Hamster anti-mouse mAb specific for the B cell survival factor, BLyS/BAFF. Treatment with both Rituximab (2mg/injection x3doses) and anti-BLyS mAb (100?g/injection x2 doses) led to B cell depletion within 10 days. BLyS/BAFF neutralization, using anti-BLyS, caused a profound depletion of mature/recirculating B cells in these mice and lasted for &amp;gt;30 days. Diabetes occurred within 2 weeks in all Rituximab treated female hCD20 Tg NOD mice (n=4); despite their early backcross generations (i.e., N4-6F1) onto the NOD genetic background. Conversely, adult female NOD/LtJ mice (n=20), B cell depleted using anti-BLyS/BAFF did not progress to diabetes for &amp;gt;30 days following treatment. Collectively, these results indicate that BLyS/BAFF neutralization may be required for the prevention of autoimmune diabetes following B lymphocyte depletion.

Pressure overload induces greater hypertrophy and mortality in female mice with p38α MAPK inhibition

We examined pressure overload left ventricular (LV) hypertrophy (H) induced by aortic banding in transgenic mice with cardiac-specific expression of a dominant negative (DN) p38α (TG) and wild type controls (WT). In response to chronic pressure overload, induced by aortic constriction, LV/BW increased more, p < 0.05, in female TG (6.4 ± 0.2, n = 7) than in WT female (5.1 ± 0.2, n = 10), or male TG or WT (5.0 ± 0.2, n = 10 vs. 5.5 ± 0.2, n = 8). Lung/BW, an index of LV decompensation, was significantly higher, p < 0.05, in banded female TG (14 ± 1.2 mg/g) than in WT females (9.0 ± 0.8), or male TG or WT (8.2 ± 0.7 vs. 9.3 ± 1.3). This was associated with higher premature mortality, p < 0.05, in banded female TG mice (42%) compared with banded WT females (10%), TG males (13%), or WT males (17%). In male, but not female, TG mice, the number of TUNEL-positive cells was smaller, p < 0.05, compared with WT. Phospho-Akt kinase activity increased ( p < 0.05) in female TG after banding, but not in males. After ovariectomy, chronic pressure overload no longer induced greater mortality, greater LVH, or p-Akt levels in female TG mice, and like male TG mice, apoptosis was protected. DN-p38α enhanced estrogen-induced activation of Akt in cultured cardiac myocytes. Thus, inhibition of p38α MAPK paradoxically augments LVH resulting in cardiac decompensation and increased mortality in response to pressure overload more in female mice than male mice, which could be due to increased Akt activation and/or through cross-talk between p38α MAPK and Akt.

Ethanol-Induced Fetal Dysmorphogenesis in the Mouse Is Diminished by High Antioxidative Capacity of the Mother

Intrauterine exposure to ethanol causes embryonic and fetal maldevelopment. Oxidative stress in mother and offspring has been suggested to be part of the teratogenic mechanism of ethanol. Here we aimed to assess the importance of maternal and fetal antioxidative capability for the risk of dysmorphogenesis in the offspring. We used male and female mice with different levels of superoxide dismutase (SOD) activity-wild-type (WT) mice, mice with a targeted SOD mutation (KO, decreased CuZnSOD mRNA), and mice transgenic for SOD (TG, increased CuZnSOD mRNA). Female WT, KO (heterozygous), and TG (heterozygous) mice were given drinking water containing 20% ethanol before and throughout gestation. Non-ethanol-exposed WT, KO, and TG mice served as controls. The female mice were mated with males with identical genotype, and the pregnancy was interrupted on gestational day 18 when the offspring was evaluated and genotyped. Fetal hepatic isoprostane (8-epi-PGF(2alpha)) levels were measured to assess the degree of fetal oxidative stress. Exposure to 20% ethanol decreased fetal weight by 9-13% in the three groups. Ethanol exposure roughly doubled the rates of maldeveloped WT and KO offspring but did not affect TG offspring. The fetal hepatic levels of 8-epi-PGF(2alpha) were increased in the ethanol-exposed WT and KO mice but not in ethanol-exposed TG mice. Ethanol exposure preferentially damaged WT fetuses in pregnant KO mice, whereas no such effect was found in the litters of ethanol-consuming TG mice. Administration of ethanol to pregnant mice disturbs embryogenesis by oxidative stress, and the adverse effects are more pronounced in offspring of mice with low antioxidative capacity.

Growth Hormone-Releasing Hormone (GHRH) Neurons in the Arcuate Nucleus (Arc) of the Hypothalamus Are Decreased in Transgenic Rats Whose Expression of Ghrelin Receptor Is Attenuated: Evidence that Ghrelin Receptor Is Involved in the Up-Regulation of GHRH Expression in the Arc

GH secretagogue (GHS)/ghrelin stimulates GH secretion by binding mainly to its receptor (GHS-R) on GHRH neurons in the arcuate nucleus (Arc) of the hypothalamus. GHRH, somatostatin, and neuropeptide Y (NPY) in the hypothalamus are involved in the regulatory mechanism of GH secretion. We previously created transgenic (Tg) rats whose GHS-R expression is reduced in the Arc, showing lower body weight and shorter nose-tail length. GH secretion is decreased in female Tg rats. To clarify how GHS-R affects GHRH expression in the Arc, we compared the numbers of GHS-R-positive, GHRH, and NPY neurons between Tg and wild-type rats. Immunohistochemical analysis showed that the numbers of GHS-R-positive neurons, GHRH neurons, and GHS-R-positive GHRH neurons were reduced in Tg rats, whereas the numbers of NPY neurons and GHS-R-positive NPY neurons did not differ between the two groups. The numbers of Fos-positive neurons and Fos-positive GHRH neurons in response to KP-102 were decreased in Tg rats. Competitive RT-PCR analysis of GHRH mRNA expression in the cultured hypothalamic neurons showed that KP-102 increased NPY mRNA expression level and that NPY decreased GHRH mRNA expression level. KP-102 increased GHRH mRNA expression level in the presence of anti-NPY IgG. GH increased somatostatin mRNA expression. Furthermore, GH and somatostatin decreased GHRH mRNA expression, whereas KP-102 showed no significant effect on somatostatin mRNA expression. These results suggest that GHS-R is involved in the up-regulation of GHRH and NPY expression and that NPY, somatostatin, and GH suppress GHRH expression. It is also suggested that the reduction of GHRH neurons of Tg rats is induced by a decrease in GHS-R expression.

Adiponectin plays an important role in efficient energy usage under energy shortage

Adiponectin is an adipose tissue-specific secretory protein known to be an insulin-sensitizing protein. In this study, we generated adiponectin sense and antisense transgenic (Tg) mice to investigate whether adiponectin plays a role in the regulation of energy homeostasis during the growth stage. Spontaneous motor activity of antisense Tg mice were markedly reduced during fasting, particularly in young female mice, compared with wild type (Wt) and sense Tg mice. Furthermore, both body weight and adipose tissue mass of the antisense female Tg mice drastically reduced during fasting. To examine the relationship between the collapse of abdominal white adipose tissue (WAT) and serum adiponectin level, we measured the expression of genes related to energy expenditure, such as uncoupling protein (UCP). Notably, the mRNA of UCP1 in the WAT of antisense Tg female mice was markedly less than that of Wt mice and the UCP1 mRNA was strongly increased during fasting. These findings suggest that the serum adiponectin is important to maintaining energy homeostasis under energy shortage conditions, such as over female pubertal development.

Differential Expression of MMPs and TIMPs in Moderate and Severe Heart Failure in a Transgenic Model

Background Altered expression of matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) accompanies the development of heart failure (HF). However, changes in MMP and TIMP protein levels or activity during the progression from compensated to decompensated failure remains incompletely examined. Methods and Results Transgenic mice (Tg) with cardiac-specific overexpression of tumor necrosis factor-α (TNF1.6) develop a sex-related, progressive cardiac dilation and HF. Echocardiographic measures were used to categorize HF severity in male (M) and female (F) Tg and wild-type (WT) mice between 4 and 50 weeks of age. Cardiac TIMPs-1, TIMPs-2, and MMP-3 (enzyme-linked immunosorbent assay), and potential (APMA-activated) MMP-9 activity were measured at similar ages. In situ zymography assessed tissue gelatinase activity. Systolic function, ventricular dimensions, and presence of pleural effusions identified severe HF in younger M Tg mice (by 18 weeks) and older F Tg (>34 weeks). Regardless of age, sex, or HF severity, Tg mice expressed significantly more TIMP-1 (Tg 119–193 pg/mg vs. WT 13–24 pg/mg, P < .001) and potential MMP-9 activity (Tg 0.41–0.58 ng/mg vs. WT 0.015–0.028 ng/mg, P < .002). M Tg expressed elevated MMP-3 (4 weeks, 0.16 ± 0.1 ng/mg protein vs. WT 0.04 ± 0.01 ng/mg, P < .003), which increased with age and HF severity (18 weeks, 0.51 ± 0.3 ng/mg P < .01). F Tg showed no increase in MMP-3 at 4 weeks but a progressive increase with age and HF severity (18 weeks 0.09 ± 0.04 ng/mg, P < .02 vs. Tg M or WT; 34 weeks 0.13 ± 0.02 ng/mg, P < .001 vs. WT). To test the hypothesis that increased MMP-3 may differentially activate MMP-9 in M Tg, in situ zymography was performed and revealed a significant increase in gelatinase activity in M Tg mice relative to both WT and F Tg. Conclusion MMP-3 may regulate activation of MMP-9/gelatinase, the progression of cardiac remodeling, and development of decompensated heart failure.

Establishment of a Diabetic Mouse Model with Progressive Diabetic Nephropathy

Although diabetic animal models exist, no single animal model develops renal changes identical to those seen in humans. Here we show that transgenic mice that overexpress inducible cAMP early repressor (ICER Igamma) in pancreatic beta cells are a good model to study the pathogenesis of diabetic nephropathy. Although ICER Igamma transgenic mice exhibit extremely high blood glucose levels throughout their lives, they survive long enough to develop diabetic nephropathy. Using this model we followed the progress of diabetic renal changes compared to those seen in humans. By 8 weeks of age, the glomerular filtration rate (GFR) was already increased, and glomerular hypertrophy was prominent. At 20 weeks, GFR reached its peak, and urine albumin excretion rate was elevated. Finally, at 40 weeks, diffuse glomerular sclerotic lesions were prominently accompanied by increased expression of collagen type IV and laminin and reduced expression of matrix metalloproteinase-2. Nodular lesions were absent, but glomerular basement membrane thickening was prominent. At this point, GFR declined and urinary albumin excretion rate increased, causing a nephrotic state with lower serum albumin and higher serum total cholesterol. Thus, similar to human diabetic nephropathy, ICER Igamma transgenic mice exhibit a stable and progressive phenotype of diabetic kidney disease due solely to chronic hyperglycemia without other modulating factors.