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1.
Int J Mol Sci ; 25(13)2024 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-39000545

RESUMO

Chemotherapy treatment against pancreatic ductal adenocarcinoma (PDAC) is thwarted by tumoral activation of multiple therapy resistance pathways. The growth hormone (GH)-GH receptor (GHR) pair is a covert driver of multimodal therapy resistance in cancer and is overexpressed in PDAC tumors, yet the therapeutic potential of targeting the same has not been explored. Here, we report that GHR expression is a negative prognostic factor in patients with PDAC. Combinations of gemcitabine with different GHR antagonists (GHRAs) markedly improve therapeutic outcomes in nude mice xenografts. Employing cultured cells, mouse xenografts, and analyses of the human PDAC transcriptome, we identified that attenuation of the multidrug transporter and epithelial-to-mesenchymal transition programs in the tumors underlie the observed augmentation of chemotherapy efficacy by GHRAs. Moreover, in human PDAC patients, GHR expression strongly correlates with a gene signature of tumor promotion and immune evasion, which corroborate with that in syngeneic tumors in wild-type vs. GH transgenic mice. Overall, we found that GH action in PDAC promoted a therapy-refractory gene signature in vivo, which can be effectively attenuated by GHR antagonism. Our results collectively present a proof of concept toward considering GHR antagonists to improve chemotherapeutic outcomes in the highly chemoresistant PDAC.


Assuntos
Carcinoma Ductal Pancreático , Desoxicitidina , Gencitabina , Neoplasias Pancreáticas , Receptores da Somatotropina , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Humanos , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Desoxicitidina/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/genética , Camundongos , Receptores da Somatotropina/metabolismo , Receptores da Somatotropina/antagonistas & inibidores , Receptores da Somatotropina/genética , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/genética , Linhagem Celular Tumoral , Camundongos Nus , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Feminino
2.
Pituitary ; 26(4): 437-450, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37353704

RESUMO

BACKGROUND: Lifelong reduction of growth hormone (GH) action extends lifespan and improves healthspan in mice. Moreover, congenital inactivating mutations of GH receptor (GHR) in mice and humans impart resistance to age-associated cancer, diabetes, and cognitive decline. To investigate the consequences of GHR disruption at an adult age, we recently ablated the GHR at 6-months of age in mature adult (6mGHRKO) mice. We found that both, male and female 6mGHRKO mice have reduced oxidative damage, with males 6mGHRKO showing improved insulin sensitivity and cancer resistance. Importantly, 6mGHRKO females have an extended lifespan compared to controls. OBJECTIVE AND METHODS: To investigate the possible mechanisms leading to health improvements, we performed RNA sequencing using livers from male and female 6mGHRKO mice and controls. RESULTS: We found that disrupting GH action at an adult age reduced the gap in liver gene expression between males and females, making gene expression between sexes more similar. However, there was still a 6-fold increase in the number of differentially expressed genes when comparing male 6mGHRKO mice vs controls than in 6mGHRKO female vs controls, suggesting that GHR ablation affects liver gene expression more in males than in females. Finally, we found that lipid metabolism and xenobiotic metabolism pathways are activated in the liver of 6mGHRKO mice. CONCLUSION: The present study shows for the first time the specific hepatic gene expression profile, cellular pathways, biological processes and molecular mechanisms that are driven by ablating GH action at a mature adult age in males and females. Importantly, these results and future studies on xenobiotic metabolism may help explain the lifespan extension seen in 6mGHRKO mice.


Assuntos
Receptores da Somatotropina , Xenobióticos , Humanos , Adulto , Camundongos , Masculino , Feminino , Animais , Lactente , Xenobióticos/metabolismo , Receptores da Somatotropina/genética , Receptores da Somatotropina/metabolismo , Fígado/metabolismo , Longevidade/genética , Expressão Gênica , Hormônio do Crescimento/metabolismo
3.
Pituitary ; 25(1): 1-51, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34797529

RESUMO

Much of our understanding of GH's action stems from animal models and the generation and characterization of genetically altered or modified mice. Manipulation of genes in the GH/IGF1 family in animals started in 1982 when the first GH transgenic mice were produced. Since then, multiple laboratories have altered mouse DNA to globally disrupt Gh, Ghr, and other genes upstream or downstream of GH or its receptor. The ability to stay current with the various genetically manipulated mouse lines within the realm of GH/IGF1 research has been daunting. As such, this review attempts to consolidate and summarize the literature related to the initial characterization of many of the known gene-manipulated mice relating to the actions of GH, PRL and IGF1. We have organized the mouse lines by modifications made to constituents of the GH/IGF1 family either upstream or downstream of GHR or to the GHR itself. Available data on the effect of altered gene expression on growth, GH/IGF1 levels, body composition, reproduction, diabetes, metabolism, cancer, and aging are summarized. For the ease of finding this information, key words are highlighted in bold throughout the main text for each mouse line and this information is summarized in Tables 1, 2, 3 and 4. Most importantly, the collective data derived from and reported for these mice have enhanced our understanding of GH action.


Assuntos
Hormônio do Crescimento , Receptores da Somatotropina , Animais , Composição Corporal , Hormônio do Crescimento/genética , Hormônio do Crescimento/metabolismo , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Camundongos , Camundongos Transgênicos , Modelos Animais , Receptores da Somatotropina/genética , Receptores da Somatotropina/metabolismo
4.
Am J Physiol Endocrinol Metab ; 320(6): E1158-E1172, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-33938235

RESUMO

In the endocrine pancreas, growth hormone (GH) is known to promote pancreatic islet growth and insulin secretion. In this study, we show that GH receptor (GHR) loss in the germline and in adulthood impacts islet mass in general but more profoundly in male mice. GHR knockout (GHRKO) mice have enhanced insulin sensitivity and low circulating insulin. We show that the total cross-sectional area of isolated islets (estimated islet mass) was reduced by 72% in male but by only 29% in female GHRKO mice compared with wild-type controls. Also, islets from GHRKO mice secreted ∼50% less glucose-stimulated insulin compared with size-matched islets from wild-type mice. We next used mice with a floxed Ghr gene to knock down the GHR in adult mice at 6 mo of age (6mGHRKO) and examined the impact on glucose and islet metabolism. By 12 mo of age, female 6mGHRKO mice had increased body fat and reduced islet mass but had no change in glucose tolerance or insulin sensitivity. However, male 6mGHRKO mice had nearly twice as much body fat, substantially reduced islet mass, and enhanced insulin sensitivity, but no change in glucose tolerance. Despite large losses in islet mass, glucose-stimulated insulin secretion from isolated islets was not significantly different between male 6mGHRKO and controls, whereas isolated islets from female 6mGHRKO mice showed increased glucose-stimulated insulin release. Our findings demonstrate the importance of GH to islet mass throughout life and that unique sex-specific adaptations to the loss of GH signaling allow mice to maintain normal glucose metabolism.NEW & NOTEWORTHY Growth hormone (GH) is important for more than just growth. GH helps to maintain pancreatic islet mass and insulin secretion throughout life. Sex-specific adaptations to the loss of GH signaling allow mice to maintain normal glucose regulation despite losing islet mass.


Assuntos
Células Germinativas/metabolismo , Hormônio do Crescimento/deficiência , Ilhotas Pancreáticas/crescimento & desenvolvimento , Ilhotas Pancreáticas/fisiologia , Receptores da Somatotropina/genética , Fatores Etários , Animais , Proliferação de Células/genética , Feminino , Células Germinativas/fisiologia , Hormônio do Crescimento/genética , Hormônio do Crescimento/metabolismo , Ilhotas Pancreáticas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Tamanho do Órgão/genética , Receptores da Somatotropina/deficiência , Receptores da Somatotropina/metabolismo , Caracteres Sexuais , Transdução de Sinais/genética
5.
Rev Endocr Metab Disord ; 22(1): 3-16, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33033978

RESUMO

Nearly one century of research using growth hormone deficient (GHD) mouse lines has contributed greatly toward our knowledge of growth hormone (GH), a pituitary-derived hormone that binds and signals through the GH receptor and affects many metabolic processes throughout life. Although delayed sexual maturation, decreased fertility, reduced muscle mass, increased adiposity, small body size, and glucose intolerance appear to be among the negative characteristics of these GHD mouse lines, these mice still consistently outlive their normal sized littermates. Furthermore, the absence of GH action in these mouse lines leads to enhanced insulin sensitivity (likely due to the lack of GH's diabetogenic actions), delayed onset for a number of age-associated physiological declines (including cognition, cancer, and neuromusculoskeletal frailty), reduced cellular senescence, and ultimately, extended lifespan. In this review, we provide details about history, availability, growth, physiology, and aging of five commonly used GHD mouse lines.


Assuntos
Modelos Animais de Doenças , Hormônio do Crescimento/deficiência , Envelhecimento , Animais , Humanos , Resistência à Insulina , Camundongos , Obesidade
6.
Pituitary ; 24(3): 438-456, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33459974

RESUMO

Progress made in the years of aging research have allowed the opportunity to explore potential interventions to slow aging and extend healthy lifespan. Studies performed in yeast, worms, flies and mice subjected to genetic and pharmacological interventions have given insight into the cellular and molecular mechanisms associated with longevity. Furthermore, it is now possible to effectively modulate pathways that slow aging at different stages of life (early life or at an adult age). Interestingly, interventions that extend longevity in adult mice have had sex-specific success, suggesting a potential link between particular pathways that modulate aging and sex. For example, reduction of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis at an adult age extends lifespan preferentially in females. Moreover, several postnatal dietary interventions tested by the 'Intervention Testing Program (ITP)' from the National Institute of Aging (NIA) have shown that while pharmacological interventions like rapamycin affect the IGF-1/insulin pathway and preferentially extend lifespan in females; dietary compounds that target other cellular pathways are effective only in male mice-indicating mutually exclusive sex-specific pathways. Therefore, a combination of interventions that target non-overlapping aging-related pathways appears to be an effective approach to further extend healthy lifespan in both sexes. Here, we review the germline and postnatal mouse lines that target the GH/IGF-1 axis as a mechanism to extend longevity as well as the dietary compounds that tested positive in the NIA program to increase lifespan. We believe that the interventions reviewed in this paper could constitute feasible combinations for an extended healthy lifespan in both male and female mice.


Assuntos
Hormônio do Crescimento Humano , Fator de Crescimento Insulin-Like I/metabolismo , Longevidade , Envelhecimento , Animais , Feminino , Hormônio do Crescimento , Masculino , Camundongos
7.
Pituitary ; 24(3): 384-399, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33433889

RESUMO

PURPOSE: Most studies that have examined the transcriptional response to GH have been performed with a single tissue. Thus, the current study performed RNASeq across three insulin-sensitive tissues of GH-treated GH deficient (GHKO) mice. METHODS: GHKO mice were injected with recombinant human GH (hGH) or vehicle daily for 5 days and adipose, liver, and muscle tissues were collected 4 h after the final injection. RNA was isolated from the tissues and sequenced. Genes that were differentially expressed between GH and vehicle treatments were further analyzed. Enrichment analysis and topology-aware pathway analysis were performed. RESULTS: GHKO mice treated with hGH had expected phenotypic alterations, with increased body, fat, fluid, liver, and muscle mass, and increased serum IGF-1 and insulin. 55 Genes were differentially expressed in all three tissues, including the canonical GH targets Igf1, Igfals, and Cish. Enrichment analysis confirmed the canonical GH response in select tissues, such as cell proliferation, metabolism, and fibrosis. The JAK/STAT pathway was the only pathway significantly altered in all three tissues. CONCLUSIONS: As expected, GH caused expression changes of many known target genes, although new candidate GH targets were identified. Liver and muscle appear to be more GH sensitive than adipose tissue due to the larger number of DEG and pathways significantly altered, but adipose still has a characteristic GH response. The diversity of changes uncovered in all three tissues after 5 days of GH treatment highlights the multiplicity of GH's effects in its target tissues.


Assuntos
Hormônio do Crescimento , Insulina , Tecido Adiposo , Animais , Perfilação da Expressão Gênica , Hormônio do Crescimento/genética , Fator de Crescimento Insulin-Like I/genética , Fígado , Camundongos
8.
Clin Proteomics ; 14: 24, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28670222

RESUMO

Growth hormone (GH) is a protein that is known to stimulate postnatal growth, counter regulate insulin's action and induce expression of insulin-like growth factor-1. GH exerts anabolic or catabolic effects depending upon on the targeted tissue. For instance, GH increases skeletal muscle and decreases adipose tissue mass. Our laboratory has spent the past two decades studying these effects, including the effects of GH excess and depletion, on the proteome of several mouse and human tissues. This review first discusses proteomic techniques that are commonly used for these types of studies. We then examine the proteomic differences found in mice with excess circulating GH (bGH mice) or mice with disruption of the GH receptor gene (GHR-/-). We also describe the effects of increased and decreased GH action on the proteome of adult patients with either acromegaly, GH deficiency or patients after short-term GH treatment. Finally, we explain how these proteomic studies resulted in the discovery of potential biomarkers for GH action, particularly those related with the effects of GH on aging, glucose metabolism and body composition.

9.
Endocr Rev ; 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38853618

RESUMO

Mouse models of growth hormone deficiency (GHD) have provided important tools for uncovering the various actions of GH. Nearly 100 years of research using these mouse lines has greatly enhanced our knowledge of the GH/IGF-1 axis. Some of the shared phenotypes of the five "common" mouse models of GHD include reduced body size, delayed sexual maturation, decreased fertility, reduced muscle mass, increased adiposity, and enhanced insulin sensitivity. Since these common mouse lines outlive their normal-sized littermates - and have protection from age-associated disease - they have become important fixtures in the aging field. On the other hand, the twelve "uncommon" mouse models of GHD described herein have tremendously divergent health outcomes ranging from beneficial aging phenotypes (similar to those described for the common models) to extremely detrimental features (such as improper development of the CNS, numerous sensory organ defects, and embryonic lethality). Moreover, advancements in next generation sequencing technologies have led to the identification of an expanding array of genes that are recognized as causative agents to numerous rare syndromes with concomitant GHD. Accordingly, this review provides researchers with a comprehensive up-to-date collection of the common and uncommon mouse models of GHD that have been used to study various aspects of physiology and metabolism associated with multiple forms of GHD. For each mouse line presented, the closest comparable human syndromes are discussed providing important parallels to the clinic.

10.
Geroscience ; 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38831184

RESUMO

Excessive growth hormone (GH) has been shown to promote joint degeneration in both preclinical and clinical studies. Little is known about the effect of disrupted GH or GH receptor (GHR) on joint health. The goal of this study is to investigate joint pathology in mice with either germline (GHR-/-) or adult inducible (iGHR-/-) GHR deficiency. Knee joints from male and female GHR-/- and WT mice at 24 months of age were processed for histological analysis. Also, knee joints from male and female iGHR-/- and WT mice at 22 months of age were scanned by micro-CT (µCT) for subchondral bone changes and characterized via histology for cartilage degeneration. Joint sections were also stained for the chondrocyte hypertrophy marker, COLX, and the cartilage degeneration marker, ADAMTS-5, using immunohistochemistry. Compared to WT mice, GHR-/- mice had remarkably smooth articular joint surfaces and an even distribution of proteoglycan with no signs of degeneration. Quantitatively, GHR-/- mice had lower OARSI and Mankin scores compared to WT controls. By contrast, iGHR-/- mice were only moderately protected from developing aging-associated OA. iGHR-/- mice had a significantly lower Mankin score compared to WT. However, Mankin scores were not significantly different between iGHR-/- and WT when males and females were analyzed separately. OARSI scores did not differ significantly between WT and iGHR-/- in either individual or combined sex analyses. Both GHR-/- and iGHR-/- mice had fewer COLX+ hypertrophic chondrocytes compared to WT, while no significant difference was observed in ADAMTS-5 staining. Compared to WT, a significantly lower trabecular thickness in the subchondral bone was observed in the iGHR-/- male mice but not in the female mice. However, there were no significant differences between WT and iGHR-/- mice in the bone volume to total tissue volume (BV/TV), bone mineral density (BMD), and trabecular number in either sex. This study identified that both germline and adult-induced GHR deficiency protected mice from developing aging-associated OA with more effective protection in GHR-/- mice.

11.
Vitam Horm ; 123: 109-149, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37717983

RESUMO

Much of our understanding of growth hormone's (GH)'s numerous activities stems from studies utilizing GH receptor (GHR) knockout mice. More recently, the role of GH action has been examined by creating mice with tissue-specific or temporal GHR disruption. To date, 37 distinct GHR knockout mouse lines have been created. Targeted tissues include fat, liver, muscle, heart, bone, brain, macrophage, intestine, hematopoietic stem cells, pancreatic ß cells, and inducible multi-tissue "global" disruption at various ages. In this chapter, a summary of each mouse line is provided with background information on the generation of the mouse line as well as important physiological outcomes resulting from GHR gene disruption. Collectively, these mouse lines provide unique insights into GH action and have resulted in the development of new hypotheses about the functions ascribed to GH action in particular tissues.


Assuntos
Encéfalo , Receptores da Somatotropina , Animais , Camundongos , Receptores da Somatotropina/genética , Coração
12.
Metabolites ; 13(2)2023 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-36837810

RESUMO

Growth hormone (GH) has established effects on protein metabolism, such as increasing protein synthesis and decreasing amino acid degradation, but its effects on circulating amino acid levels are less studied. To investigate this relationship, metabolomic analyses were used to measure amino acid concentrations in plasma and feces of mice with alterations to the GH axis, namely bovine GH transgenic (bGH; increased GH action) and GH receptor knockout (GHRKO; GH resistant) mice. To determine the effects of acute GH treatment, GH-injected GH knockout (GHKO) mice were used to measure serum glycine. Furthermore, liver gene expression of glycine metabolism genes was assessed in bGH, GHRKO, and GH-injected GHKO mice. bGH mice had significantly decreased plasma glycine and increased hydroxyproline in both sexes, while GHRKO mice had increased plasma glycine in both sexes and decreased hydroxyproline in males. Glycine synthesis gene expression was decreased in bGH mice (Shmt1 in females and Shmt2 in males) and increased in GHRKO mice (Shmt2 in males). Acute GH treatment of GHKO mice caused decreased liver Shmt1 and Shmt2 expression and decreased serum glycine. In conclusion, GH alters circulating glycine and hydroxyproline levels in opposing directions, with the glycine changes at least partially driven by decreased glycine synthesis.

13.
Front Physiol ; 13: 867921, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35665221

RESUMO

Growth hormone (GH) is a peptide hormone that can signal directly through its receptor or indirectly through insulin-like growth factor 1 (IGF-1) stimulation. GH draws its name from its anabolic effects on muscle and bone but also has distinct metabolic effects in multiple tissues. In addition to its metabolic and musculoskeletal effects, GH is closely associated with aging, with levels declining as individuals age but GH action negatively correlating with lifespan. GH's effects have been studied in human conditions of GH alteration, such as acromegaly and Laron syndrome, and GH therapies have been suggested to combat aging-related musculoskeletal diseases, in part, because of the decline in GH levels with advanced age. While clinical data are inconclusive, animal models have been indispensable in understanding the underlying molecular mechanisms of GH action. This review will provide a brief overview of the musculoskeletal effects of GH, focusing on clinical and animal models.

14.
Endocrinology ; 163(10)2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35952979

RESUMO

Growth hormone receptor knockout (GHRKO) mice have been used for 25 years to uncover some of the many actions of growth hormone (GH). Since they are extremely long-lived with enhanced insulin sensitivity and protected from multiple age-related diseases, they are often used to study healthy aging. To determine the effect that adipose tissue has on the GHRKO phenotype, our laboratory recently created and characterized adipocyte-specific GHRKO (AdGHRKO) mice, which have increased adiposity but appear healthy with enhanced insulin sensitivity. To test the hypothesis that removal of GH action in adipocytes might partially replicate the increased lifespan and healthspan observed in global GHRKO mice, we assessed adiposity, cytokines/adipokines, glucose homeostasis, frailty, and lifespan in aging AdGHRKO mice of both sexes. Our results show that disrupting the GH receptor gene in adipocytes improved insulin sensitivity at advanced age and increased lifespan in male AdGHRKO mice. AdGHRKO mice also exhibited increased fat mass, reduced circulating levels of insulin, c-peptide, adiponectin, resistin, and improved frailty scores with increased grip strength at advanced ages. Comparison of published mean lifespan data from GHRKO mice to that from AdGHRKO and muscle-specific GHRKO mice suggests that approximately 23% of lifespan extension in male GHRKO is due to GHR disruption in adipocytes vs approximately 19% in muscle. Females benefited less from GHR disruption in these 2 tissues with approximately 19% and approximately 0%, respectively. These data indicate that removal of GH's action, even in a single tissue, is sufficient for observable health benefits that promote long-term health, reduce frailty, and increase longevity.


Assuntos
Fragilidade , Resistência à Insulina , Adipócitos , Animais , Feminino , Hormônio do Crescimento , Resistência à Insulina/genética , Fator de Crescimento Insulin-Like I/genética , Longevidade/genética , Masculino , Camundongos , Camundongos Knockout , Receptores da Somatotropina/genética
15.
Front Oncol ; 12: 936145, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35865483

RESUMO

Knockdown of GH receptor (GHR) in melanoma cells in vitro downregulates ATP-binding cassette-containing (ABC) transporters and sensitizes them to anti-cancer drug treatments. Here we aimed to determine whether a GHR antagonist (GHRA) could control cancer growth by sensitizing tumors to therapy through downregulation of ABC transporters in vivo. We intradermally inoculated Fluc-B16-F10 mouse melanoma cells into GHA mice, transgenic for a GHR antagonist (GHRA), and observed a marked reduction in tumor size, mass and tumoral GH signaling. Moreover, constitutive GHRA production in the transgenic mice significantly improved the response to cisplatin treatment by suppressing expression of multiple ABC transporters and sensitizing the tumors to the drug. We confirmed that presence of a GHRA and not a mere absence of GH is essential for this chemo-sensitizing effect using Fluc-B16-F10 allografts in GH knockout (GHKO) mice, where tumor growth was reduced relative to that in GH-sufficient controls but did not sensitize the tumor to cisplatin. We extended our investigation to hepatocellular carcinoma (HCC) using human HCC cells in vitro and a syngeneic mouse model of HCC with Hepa1-6 allografts in GHA mice. Gene expression analyses and drug-efflux assays confirm that blocking GH significantly suppresses the levels of ABC transporters and improves the efficacy of sorafenib towards almost complete tumor clearance. Human patient data for melanoma and HCC show that GHR RNA levels correlate with ABC transporter expression. Collectively, our results validate in vivo that combination of a GHRA with currently available anti-cancer therapies can be effective in attacking cancer drug resistance.

16.
Aging Cell ; 20(12): e13506, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34811874

RESUMO

Studies in multiple species indicate that reducing growth hormone (GH) action enhances healthy lifespan. In fact, GH receptor knockout (GHRKO) mice hold the Methuselah prize for the world's longest-lived laboratory mouse. We previously demonstrated that GHR ablation starting at puberty (1.5 months), improved insulin sensitivity and female lifespan but results in markedly reduced body size. In this study, we investigated the effects of GHR disruption in mature-adult mice at 6 months old (6mGHRKO). These mice exhibited GH resistance (reduced IGF-1 and elevated GH serum levels), increased body adiposity, reduced lean mass, and minimal effects on body length. Importantly, 6mGHRKO males have enhanced insulin sensitivity and reduced neoplasms while females exhibited increased median and maximal lifespan. Furthermore, fasting glucose and oxidative damage was reduced in females compared to males irrespective of Ghr deletion. Overall, disrupted GH action in adult mice resulted in sexual dimorphic effects suggesting that GH reduction at older ages may have gerotherapeutic effects.


Assuntos
Insulina/metabolismo , Receptores da Somatotropina/genética , Envelhecimento , Animais , Feminino , Masculino , Camundongos , Transdução de Sinais
17.
Aging Cell ; 20(12): e13505, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34811875

RESUMO

Somatopause refers to the gradual declines in growth hormone (GH) and insulin-like growth factor-1 throughout aging. To define how induced somatopause affects skeletal integrity, we used an inducible GH receptor knockout (iGHRKO) mouse model. Somatopause, induced globally at 6 months of age, resulted in significantly more slender bones in both male and female iGHRKO mice. In males, induced somatopause was associated with progressive expansion of the marrow cavity leading to significant thinning of the cortices, which compromised bone strength. We report progressive declines in osteocyte lacunar number, and increases in lacunar volume, in iGHRKO males, and reductions in lacunar number accompanied by ~20% loss of overall canalicular connectivity in iGHRKO females by 30 months of age. Induced somatopause did not affect mineral/matrix ratio assessed by Raman microspectroscopy. We found significant increases in bone marrow adiposity and high levels of sclerostin, a negative regulator of bone formation in iGHRKO mice. Surprisingly, however, despite compromised bone morphology, osteocyte senescence was reduced in the iGHRKO mice. In this study, we avoided the confounded effects of constitutive deficiency in the GH/IGF-1 axis on the skeleton during growth, and specifically dissected its effects on the aging skeleton. We show here, for the first time, that induced somatopause compromises bone morphology and the bone marrow environment.


Assuntos
Composição Corporal/fisiologia , Doenças Ósseas Metabólicas/fisiopatologia , Hormônio do Crescimento/efeitos adversos , Análise Espectral Raman/métodos , Envelhecimento , Animais , Feminino , Masculino , Camundongos
18.
Growth Horm IGF Res ; 51: 1-5, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31923746

RESUMO

The Growth hormone receptor (GHR) is expressed in many cells/tissues in the body. To investigate the specific metabolic effects of GH action in distinct tissues, several tissue-specific GHR gene disrupted or knockout (KO) mouse lines have been generated. Previously, we have described the effects of GHRKO in several known insulin sensitive tissues, namely liver, muscle and adipose tissue. In this review, we further explore and summarize the main findings of recently published GHRKO results in liver, adipocytes, intestine, bone, brain and heart.


Assuntos
Glicemia/metabolismo , Hormônio do Crescimento/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Insulina/metabolismo , Receptores da Somatotropina/genética , Adipócitos/metabolismo , Adipócitos/patologia , Animais , Osso e Ossos/metabolismo , Osso e Ossos/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Técnicas de Inativação de Genes , Coração , Resistência à Insulina , Mucosa Intestinal/metabolismo , Intestinos/patologia , Fígado/metabolismo , Fígado/patologia , Camundongos , Camundongos Knockout , Modelos Animais , Miocárdio/metabolismo , Miocárdio/patologia
19.
Mol Cell Endocrinol ; 515: 110919, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32592744

RESUMO

Growth hormone (GH) is pituitary derived hormone which acts on most tissues of the body either directly or indirectly and affects many metabolic processes throughout life. Genetically engineered mouse lines have become vital tools for uncovering the various in vivo activities of a GH. A particularly useful mouse line has been the GH receptor (GHR) gene disrupted or knockout (KO) mouse which has been used world-wide in many studies. Recent advances in biotechnology have allowed the development of tissue-specific knockout mouse lines which allows for more direct enquiries on the activities of a given protein in specific tissues or cell types. Accordingly, twenty-two novel tissue-specific GHRKO mouse lines have been developed in the last eleven years. In this paper we provide a detailed list and review the phenotypic changes that occur in each of these tissue-specific GHRKO mouse lines.


Assuntos
Hormônio do Crescimento/metabolismo , Receptores da Somatotropina/metabolismo , Animais , Humanos , Camundongos Knockout , Hipófise/metabolismo
20.
J Neuroendocrinol ; 32(11): e12893, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33043505

RESUMO

Bovine growth hormone (bGH) transgenic mice mimic the clinical condition of acromegaly, having high circulating growth hormone (GH) levels. These mice are giant, have decreased adipose tissue (AT) mass, impaired glucose metabolism and a shortened lifespan. The detrimental effects of excess GH have been suggested, in part, to be a result of its depot-specific actions on AT. To investigate this relationship, we evaluated gene expression, biological mechanisms, cellular pathways and predicted microRNA (miRNA) in two AT depots (subcutaneous [Subq] and epididymal [Epi]) from bGH and littermate controls using RNA sequencing analysis. Two analyses on the differentially expressed genes (DEG) were performed: (i) comparison of the same AT depot between bGH and wild-type (WT) mice (genotype comparison) and (ii) comparison of Subq and Epi AT depots within the same genotype (depot comparison). For the genotype comparison, we found a higher number of significant DEG in the Subq AT depot of bGH mice compared to WT controls, corroborating previous reports that GH has a greater impact on the Subq depot. Furthermore, most of the DEG in bGH mice were not shared by WT mice, suggesting that excess GH induces the expression of genes not commonly present in AT. Through gene ontology and pathway analysis, the genotype comparison revealed that the DEG of the Subq depot of bGH mice relate to fatty acid oxidation, branched-chain amino acid degradation and the immune system. Additionally, the AT depot comparison showed that the immune cell activation and T-cell response appear up-regulated in the Subq compared to the Epi AT depot. The miRNA prediction also suggested a modulation of T-cell-related biological process in Subq. In summary, the present study provides a unique resource for understanding the specific differences in gene expression that are driven by both excess GH action and AT depot location.


Assuntos
Tecido Adiposo/metabolismo , Hormônio do Crescimento/genética , Hormônio do Crescimento/metabolismo , Aminoácidos de Cadeia Ramificada/metabolismo , Animais , Bovinos , Epididimo/metabolismo , Ácidos Graxos/metabolismo , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/fisiologia , Genótipo , Sistema Imunitário/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , MicroRNAs/biossíntese , MicroRNAs/genética , Oxirredução , Transdução de Sinais/genética , Gordura Subcutânea/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo
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