Peptides that regulate feeding behavior via the brain may also regulate energy storage and expenditure in the adipose tissue, a system collectively known as the "brain-fat axis". Neuropeptide Y (NPY) is orexigenic and promotes adipogenesis in both birds and mammals, although mechanisms in adipose tissue are unclear. The first objective was thus to evaluate effects of NPY on chick preadipocyte proliferation and differentiation. Preadipocytes were treated with NPY and gene expression and cellular proliferation were evaluated. Cells were also treated with NPY during differentiation and harvested during the later stages. With increased gene expression of proliferation markers in preadipocytes, and during differentiation increased expression of adipogenesis-associated factors, increased lipid accumulation, and increased activity of an adipogenic enzyme, glycerol-3-phosphate dehydrogenase, results suggest that NPY may enhance preadipocyte activity and adipogenesis and promotes lipid accumulation throughout chicken adipocyte differentiation. Another appetite-regulatory peptide, alpha-melanocyte stimulating hormone (α-MSH), is anorexigenic and mediates lipolysis in adipose tissue, but effects on fat in avians are unreported. The second objective was thus to determine the effects of exogenous α-MSH on adipose tissue physiology in broiler chicks. Chicks were intraperitoneally injected with α-MSH and adipose tissue and plasma collected. Cells isolated from abdominal fat of a different set of chicks were treated with α-MSH. Results suggest that α-MSH increases lipolysis and reduces adipogenesis in chick adipose tissue. Collectively, results of this research provide insights on how appetite-regulatory peptides like NPY and α-MSH affect adipose tissue physiology, thereby playing important roles in regulating whole-body energy balance. / Master of Science

No description available.

La cicatrisation parodontale est un processus complexe, composé de quatre phases hautement intégrées (hémostase, inflammation, prolifération, remodelage), qui nécessite une interaction complexe entre les différents types tissulaires (épithélium, conjonctif, os) ainsi que la synthèse de médiateurs, tels que les hormones et les facteurs de croissance. La difficulté à pouvoir obtenir une régénération des tissus parodontaux est en partie due à la réponse inflammatoire qui interfère avec le processus de cicatrisation, via la surexpression des cytokines pro-inflammatoires, ainsi qu’à la croissance rapide des cellules épithéliales le long de la surface de la racine qui porte atteinte à la vraie organisation des tissus, essentielle à la régénération parodontale. Notre objectif a été de mettre au point des membranes nanofibreuses implantables à base de polycaprolactone (PCL) fonctionnalisés par plusieurs molécules actives (Alpha-Melanocyte Stimulating Hormone (α-MSH)), ibuprofène, atorvastatine) et implantables, permettant à la fois un contrôle physique et biochimique de la cicatrisation parodontale. En d’autres termes, nous avons cherché à ralentir la colonisation de la surface radiculaire par les cellules épithéliales et à moduler l’inflammation de la phase post-chirurgicale afin de promouvoir la cicatrisation parodontale. Pour cela, nous avons mis au point un modèle d’inflammation in vitro mimant le tissu superficiel du parodonte en utilisant des cellules parodontales, à savoir des kératinocytes et fibroblastes gingivaux humains, stimulées par du lipopolysaccharide de Porphyromonas gingivalis (LPS-Pg). Les résultats obtenus ont montré une bonne biocompatibilité des systèmes (α-MSH, ibuprofène) ainsi qu’une diminution de la prolifération, migration des kératinocytes, fibroblastes gingivaux humains et une diminution significative de l’expression des marqueurs pro- ou anti-inflammatoires (TNF-α, TGF-β, IL-6, IL-8), des marqueurs d’adhérence, de prolifération (Intégrine, Laminine, Fibronectine) et de remodelage (COL-IV). En conclusion, les stratégies développées (α-MSH, ibuprofène) au sein de notre laboratoire ont permis de mettre en évidence l’intérêt de délivrer une molécule anti-inflammatoire à partir d’un biomatériau et représentent un fort potentiel d’application clinique pour la parodontologie mais aussi pour la médecine de demain. / Periodontal wound healing is a process involving hemostasis, inflammatory phase, proliferation and maturation/matrix remodeling. These phases require cell-to-cell interaction of different cell types (epithelial cells, fibroblasts, osteoblasts, and cementoblasts) orchestrated by growth factors, cytokines and extracellular matrix components. After conventional periodontal therapy, wound healing corresponds more to tissue reparation than regeneration. This absence of true regeneration is considered to be mainly due to the competition between the different periodontal tissues (gingiva, cementum, alveolar bone) and the differential rate of proliferation, migration and differentiation of periodontal cells during wound healing. Therefore, the inflammatory response could interfere with the healing process depending on the secretion/activity level of matrix metalloproteinase (MMPs), cytokines, chemokines and also the imbalance with their antagonists/inhibitors, which leads to fibrosis and excessive scarring. Our aim was to develop implantable nano-fibrous membranes based on polycaprolactone (PCL) and functionalized by several active molecules (Alpha-melanocyte stimulating hormone (α-MSH)), ibuprofen, atorvastatin) allowing both physical control and biochemical periodontal healing features. Furthermore, we developed an in vitro inflammatory model mimicking the periodontal tissue surface, using periodontal cells ; keratinocytes and human gingival fibroblasts stimulated with lipopolysaccharide of Porphyromonas gingivalis (Pg-LPS). The results obtained showed good biocompatibility systems (α-MSH, ibuprofen) and a decrease in the proliferation and migration of keratinocytes, human gingival fibroblasts. Moreover, a significant decrease of pro- or anti-inflammatory markers expression (TNF-α, TGF-β, IL-6, IL-8), adhesion markers of proliferation (Integrin, laminin, fibronectin) and remodeling (COL-IV) could be achieved. In conclusion, the strategies developed in our laboratory (α-MSH, ibuprofen), have helped to highlight the interest of the release of an anti-inflammatory molecule from a biomaterial, and represented a strong potential for clinical application not only in periodontics but also in general medicine.

O hormônio alfa estimulador de melanócito (alfa-MSH) é um neuropeptídeo com atividade anti-inflamatória que apresenta efeitos benéficos em modelos experimentais de doenças autoimunes. Entretanto pouca atenção tem sido dada a seus efeitos no lúpus eritematoso sistêmico (LES). No presente estudo utilizou-se o tratamento com o super análogo NDP-MSH em modelo experimental de LES induzido por pristane. Grupos de camundongos fêmeas foram tratados diariamente com 1,25 mg/Kg de NDP-MSH ou solução salina por 180 dias. Foram avaliados os seguintes parâmetros séricos: isotipos de IgG, anticorpos antinucleares (FAN) e citocinas. A intensidade da artrite foi mensurada por graduação de edema e eritema. A função renal foi estimada por proteinúria e escore histopatológico. A expressão de IgG, alfa-SMA, iNOS, C3, CD3, MC1R, CRF e alfa-MSH glomerular foi quantificada por imunohistoquímica. Camundongos com LES apresentaram aumento de IgG, FAN, IL-6, IL-10 e TNFalfa, escore de artrite, disfunção renal e celularidade mesangial quando comparados aos animais controle normais. O tratamento dos animais LES com NDP-MSH reduziu os títulos de IgG1 e IgG2a (p < 0,05 e p < 0,001 respectivamente), bem como a incidência de FAN+ (p < 0,05). Níveis séricos de IL-6 e IL-10 foram abrandados e houve aumento dos níveis de TNFalfa (p < 0,05). O escore de artrite foi reduzido em 70% (p < 0,01). A proteinúria não foi afetada pelo tratamento, entretanto houve 50% de redução do grau de lesão glomerular (p < 0,05). A avaliação imunohistoquímica mostrou que o tratamento reduziu os depósitos de IgG e a expressão de alfa-SMA e iNOS glomerular (p < 0,01; p < 0,01 e p < 0,05 respectivamente). A expressão do receptor MC1R foi menor nos grupos LES, tratados ou não. A expressão de alfa-MSH e CRF estavam diminuídas somente no grupo tratado com NDP-MSH enquanto a expressão de C3 e CD3 não diferiu entre os grupos. Em conjunto nossos resultados sugerem, pela primeira vez, que a o tratamento com o análogo de alfa-MSH melhora a atividade da doença em modelo experimental de LES / Alpha-melanocyte stimulating hormone (alfa-MSH) is a neuropeptide with anti-inflammatory activity that has beneficial effects in experimental models of autoimmune diseases. However little attention has been paid to its effects on systemic lupus erythematosus (SLE). Herein we employed the treatment with the super analogue NDP-MSH in experimental SLE induced by pristane. Groups of female mice were treated daily with 1.25 mg/Kg of NDP-MSH (SLE-MSH) or saline for 180 days. The following parameters were evaluated: serum IgG isotypes, antinuclear antibodies (ANA) and cytokines. Arthritis was graded by edema and erythema in each paw. Renal function was estimated by proteinuria and histopathological score. The expression of IgG, alfa-SMA, iNOS, C3, CD3, MC1R, CRF and alfa-MSH was quantified by immunohistochemistry in glomerulus. SLE mice presented increased IgG levels, ANA, IL-6, IL-10 and TNFalfa, arthritis incidence, renal dysfunction and mesangial cellularity when compared with normal animals. Animals SLE-MSH presented reduction of IgG1 and IgG2a titles (p < 0.05 and p < 0.001 respectively), as well as the incidence of FAN+ (p < 0.05). The treatment reduced IL-6 and IL-10 serum levels and increase of TNFalfa levels (p < 0.05). Arthritis score was reduced in 70% in SLE-MSH animals (p < 0.01). Proteinuria was not affected by the treatment, however it was registered a 50% reduction of the glomerular lesion (p < 0.05). The immunohistochemical evaluation revealed reduced IgG deposits and glomerular expression of alfa-SMA and iNOS in SLE-MSH animals (p < 0.01, p < 0.01 and p < 0.05 vs.LES, respectively). MC1R was sub expressed in SLE animals, treated or not. The expression of alfa-MSH and CRF were impaired only in the SLE-MSH group. Taken together our results suggest for the first time that treatment with alfa-MSH analogue improve disease activity in an experimental model of SLE

O hormônio alfa estimulador de melanócito (alfa-MSH) é um neuropeptídeo com atividade anti-inflamatória que apresenta efeitos benéficos em modelos experimentais de doenças autoimunes. Entretanto pouca atenção tem sido dada a seus efeitos no lúpus eritematoso sistêmico (LES). No presente estudo utilizou-se o tratamento com o super análogo NDP-MSH em modelo experimental de LES induzido por pristane. Grupos de camundongos fêmeas foram tratados diariamente com 1,25 mg/Kg de NDP-MSH ou solução salina por 180 dias. Foram avaliados os seguintes parâmetros séricos: isotipos de IgG, anticorpos antinucleares (FAN) e citocinas. A intensidade da artrite foi mensurada por graduação de edema e eritema. A função renal foi estimada por proteinúria e escore histopatológico. A expressão de IgG, alfa-SMA, iNOS, C3, CD3, MC1R, CRF e alfa-MSH glomerular foi quantificada por imunohistoquímica. Camundongos com LES apresentaram aumento de IgG, FAN, IL-6, IL-10 e TNFalfa, escore de artrite, disfunção renal e celularidade mesangial quando comparados aos animais controle normais. O tratamento dos animais LES com NDP-MSH reduziu os títulos de IgG1 e IgG2a (p < 0,05 e p < 0,001 respectivamente), bem como a incidência de FAN+ (p < 0,05). Níveis séricos de IL-6 e IL-10 foram abrandados e houve aumento dos níveis de TNFalfa (p < 0,05). O escore de artrite foi reduzido em 70% (p < 0,01). A proteinúria não foi afetada pelo tratamento, entretanto houve 50% de redução do grau de lesão glomerular (p < 0,05). A avaliação imunohistoquímica mostrou que o tratamento reduziu os depósitos de IgG e a expressão de alfa-SMA e iNOS glomerular (p < 0,01; p < 0,01 e p < 0,05 respectivamente). A expressão do receptor MC1R foi menor nos grupos LES, tratados ou não. A expressão de alfa-MSH e CRF estavam diminuídas somente no grupo tratado com NDP-MSH enquanto a expressão de C3 e CD3 não diferiu entre os grupos. Em conjunto nossos resultados sugerem, pela primeira vez, que a o tratamento com o análogo de alfa-MSH melhora a atividade da doença em modelo experimental de LES / Alpha-melanocyte stimulating hormone (alfa-MSH) is a neuropeptide with anti-inflammatory activity that has beneficial effects in experimental models of autoimmune diseases. However little attention has been paid to its effects on systemic lupus erythematosus (SLE). Herein we employed the treatment with the super analogue NDP-MSH in experimental SLE induced by pristane. Groups of female mice were treated daily with 1.25 mg/Kg of NDP-MSH (SLE-MSH) or saline for 180 days. The following parameters were evaluated: serum IgG isotypes, antinuclear antibodies (ANA) and cytokines. Arthritis was graded by edema and erythema in each paw. Renal function was estimated by proteinuria and histopathological score. The expression of IgG, alfa-SMA, iNOS, C3, CD3, MC1R, CRF and alfa-MSH was quantified by immunohistochemistry in glomerulus. SLE mice presented increased IgG levels, ANA, IL-6, IL-10 and TNFalfa, arthritis incidence, renal dysfunction and mesangial cellularity when compared with normal animals. Animals SLE-MSH presented reduction of IgG1 and IgG2a titles (p < 0.05 and p < 0.001 respectively), as well as the incidence of FAN+ (p < 0.05). The treatment reduced IL-6 and IL-10 serum levels and increase of TNFalfa levels (p < 0.05). Arthritis score was reduced in 70% in SLE-MSH animals (p < 0.01). Proteinuria was not affected by the treatment, however it was registered a 50% reduction of the glomerular lesion (p < 0.05). The immunohistochemical evaluation revealed reduced IgG deposits and glomerular expression of alfa-SMA and iNOS in SLE-MSH animals (p < 0.01, p < 0.01 and p < 0.05 vs.LES, respectively). MC1R was sub expressed in SLE animals, treated or not. The expression of alfa-MSH and CRF were impaired only in the SLE-MSH group. Taken together our results suggest for the first time that treatment with alfa-MSH analogue improve disease activity in an experimental model of SLE

alpha-melanocyte stimulating hormone (alpha-MSH) is an important regulator of food intake, metabolic rate, and inflammation. Recently, alpha-MSH was shown to influence sympathetic activity and blood pressure regulation. In the present study, we investigated the cardiovascular effects of alpha-MSH in the nucleus tractus solitarii (NTS) of spontaneously hypertensive rats (SHR). Because nitric oxide (NO) is well-known to involve in central cardiovascular regulation, we elucidated the role of NO in the cardiovascular responses induced by alpha-MSH. In urethane-anesthetized SHR, unilateral microinjection of alpha-MSH (0.3-300 pmol) into the NTS produced dose-responsive depressor and bradycardic effects. The cardiovascular effects of alpha-MSH were abrogated by the antagonist of melanocortin receptor (MC3/4-R), SHU9119. Pretreatment with precursor of nitric oxide, L-arginine, enhanced the duration of alpha-MSH-mediated hypotensive effects, whereas prior application of L-NAME, a universal inhibitor of nitric oxide synthase (NOS), significantly attenuated the effects of alpha-MSH. Prior injection with inhibitor of inducible NOS, aminoguanidine, but not inhibitor of neuronal NOS, 7-nitroindazole, attenuated the hypotensive effect of alpha-MSH. In summary, these results indicated alpha-MSH induced depressor and bradycardic effects in the NTS of SHR. Besides, the hypotensive mechanism of alpha-MSH was mediated via MC4-R and involved with iNOS activation in the NTS of SHR.

Communication signals are shaped by the opposing selection pressures imposed by predators and mates. A dynamic signal might serve as an adaptive compromise between an inconspicuous signal that evades predators and an extravagant signal preferred by females. Such a signal has been described in the gymnotiform electric fish, Brachyhypopomus gauderio, which produces a sexually dimorphic electric organ discharge (EOD). The EOD varies on a circadian rhythm and in response to social cues. This signal plasticity is mediated by the slow action of androgens and rapid action of melanocortins. My dissertation research tested the hypotheses that (1) signal plasticity is related to sociality levels in gymnotiform species, and (2) differences in signal plasticity are regulated by differential sensitivity to androgen and melanocortin hormones. To assess the breadth of dynamic signaling within the order Gymnotiformes, I sampled 13 species from the five gymnotiform families. I recorded EODs to observe spontaneous signal oscillations after which I injected melanocortin hormones, saline control, or presented the fish with a conspecific. I showed that through the co-option of the ancient melanocortin pathway, gymnotiforms dynamically regulate EOD amplitude, spectral frequency, both, or neither. To investigate whether observed EOD plasticities are related to species-specific sociality I tested four species; two territorial, highly aggressive species, Gymnotus carapo and Apteronotus leptorhynchus, a highly gregarious species, Eigenmannia cf. virescens, and an intermediate short-lived species with a fluid social system, Brachyhypopomus gauderio. I examined the relationship between the androgens testosterone and 11-ketotestosterone, the melanocortin a-MSH, and their roles in regulating EOD waveform. I implanted all fish with androgen and blank silicone implants, and injected with a-MSH before and at the peak of implant effect. I found that waveforms of the most territorial and aggressive species were insensitive to hormone treatments; maintaining a static, stereotyped signal that preserves encoding of individual identity. Species with a fluid social system were most responsive to hormone treatments, exhibiting signals that reflect immediate condition and reproductive state. In conclusion, variation in gymnotiform signal plasticity is hormonally regulated and seems to reflect species-specific sociality.