Novel endogenous peptide agonists of cannabinoid receptors

Hemopressin (Hp), a 9-residue alpha-hemoglobin-derived peptide, was previously reported to function as a CB(1) cannabinoid receptor antagonist (1). In this study, we report that mass spectrometry (MS) data from peptidomics analyses of mouse brain extracts identified N-terminally extended forms of Hp containing either three (RVD-Hp alpha) or two (VD-Hp alpha) additional amino acids, as well as a beta-hemoglobinderived peptide with sequence similarity to that of hemopressin (VD-Hp beta). Characterization of the alpha-hemoglobin-derived peptides using binding and functional assays shows that in contrast to Hp, which functions as a CB(1) cannabinoid receptor antagonist, both RVD-Hp alpha and VD-Hp alpha function as agonists. Studies examining the increase in the phosphorylation of ERK1/2 levels or release of intracellular Ca(2+) indicate that these peptides activate a signal transduction pathway distinct from that activated by the endo-cannabinoid, 2-arachidonoylglycerol, or the classic CB(1) agonist, Hu-210. This finding suggests an additional mode of regulation of endogenous cannabinoid receptor activity. Taken together, these results suggest that the CB(1) receptor is involved in the integration of signals from both lipid-and peptide-derived signaling molecules.-Gomes, I., Grushko, J. S., Golebiewska, U., Hoogendoorn, S., Gupta, A., Heimann, A. S., Ferro, E. S., Scarlata, S., Fricker, L. D., Devi, L. A. Novel endogenous peptide agonists of cannabinoid receptors. FASEB J. 23, 3020-3029 (2009). www.fasebj.org

The Central Nervous System as Target for Antihypertensive Actions of a Proline-Rich Peptide from Bothrops jararaca Venom

Pyroglutamyl proline-rich oligopeptides, present in the venom of the pit viper Bothrops jararaca (Bj-PROs), are the first described naturally occurring inhibitors of the angiotensin I-converting enzyme (ACE). The inhibition of ACE by the decapeptide Bj-PRO-10c (intracellular calcium concentration ([Ca(2+)](i)) in primary culture from postnatal rat brain. The N-terminal sequence of the peptide was not essential for induction of calcium fluxes, while any changes of C-terminal Pro or Ile residues affected Bj-PRO-10c`s activity. Using calcium imaging by confocal microscopy and fluorescence imaging plate reader analysis, we have characterized Bj-PRO-10c-induced [Ca(2+)](i) transients in rat brain cells as being independent from bradykinin-mediated effects and ACE inhibition. Bj-PRO-10c induced pertussis toxin-sensitive G(i/o)-protein activity mediated through a yet unknown receptor, influx and liberation of calcium from intracellular stores, as well as reduction of intracellular cAMP levels. Bj-PRO-10c promoted glutamate and GABA release that may be responsible for its antihypertensive activity and its effect on HR. (C) 2010 International Society for Advancement of Cytometry

Increased Activation of Stromal Interaction Molecule-1/Orai-1 in Aorta From Hypertensive Rats A Novel Insight Into Vascular Dysfunction

Disturbances in the regulation of cytosolic calcium (Ca(2+)) concentration play a key role in the vascular dysfunction associated with arterial hypertension. Stromal interaction molecules (STIMs) and Orai proteins represent a novel mechanism to control store-operated Ca(2+) entry. Although STIMs act as Ca(2+) sensors for the intracellular Ca(2+) stores, Orai is the putative pore-forming component of Ca(2+) release-activated Ca(2+) channels at the plasma membrane. We hypothesized that augmented activation of Ca(2+) release-activated Ca(2+)/Orai-1, through enhanced activity of STIM-1, plays a role in increased basal tonus and vascular reactivity in hypertensive animals. Endothelium-denuded aortic rings from Wistar-Kyoto and stroke-prone spontaneously hypertensive rats were used to evaluate contractions because of Ca(2+) influx. Depletion of intracellular Ca(2+) stores, which induces Ca(2+) release-activated Ca(2+) activation, was performed by placing arteries in Ca(2+) free-EGTA buffer. The addition of the Ca(2+) regular buffer produced greater contractions in aortas from stroke-prone spontaneously hypertensive rats versus Wistar-Kyoto rats. Thapsigargin (10 mu mol/L), an inhibitor of the sarcoplasmic reticulum Ca(2+) ATPase, further increased these contractions, especially in stroke-prone spontaneously hypertensive rat aorta. Addition of the Ca(2+) release-activated Ca(2+) channel inhibitors 2-aminoethoxydiphenyl borate (100 mu mol/L) or gadolinium (100 mu mol/L), as well as neutralizing antibodies to STIM-1 or Orai-1, abolished thapsigargin-increased contraction and the differences in spontaneous tone between the groups. Expression of Orai-1 and STIM-1 proteins was increased in aorta from stroke-prone spontaneously hypertensive rats when compared with Wistar-Kyoto rats. These results support the hypothesis that both Orai-1 and STIM-1 contribute to abnormal vascular function in hypertension. Augmented activation of STIM-1/Orai-1 may represent the mechanism that leads to impaired control of intracellular Ca(2+) levels in hypertension. (Hypertension. 2009; 53[part 2]: 409-416.)

Efeito do tratamento com as drogas antipsicóticas haloperidol e clozapina sobre a infecção de toxoplasma gondii em cultura de células retinianas embrionárias

T. gondii is an obligate intracellular protozoan and the main cause of retinochoroiditis in humans. The aim of this study was to evaluate the effect of the antipsychotic drugs haloperidol and clozapine on the course of infection by T. gondii of cultured embryonic retinal cells. Embryo retinas of Gallus gallus domesticus (E12) were used for the preparation of mixed monolayer cultures of retinal cells. Cultures were maintained on plates of 96 and 24 wells by 37°C in DMEM medium supplemented with 5% fetal bovine serum for 2 days. After this period, cultures were simultaneously infected with tachyzoites of T. gondii and treated with the antipsychotics haloperidol and clozapine for 48 hours. Treatment effects were determined by both assessing cell viability with the MTT method and evaluating infection outcomes in slides stained with Giemsa. The treatment with haloperidol and clozapine cells infected with T. gondii resulted in higher viability of these cells, suggesting a possible prevention of neuronal degeneration induced by T. gondii. Additionally, intracellular replication of this protozoan in cells treated with haloperidol and clozapine were significantly reduced, possibly by modulation of the parasite s intracellular calcium concentration

Obesity induces upregulation of genes involved in myocardial Ca2+ handling

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exercício e restrição alimentar aumentam o RNAm de proteínas do trânsito de Ca2+ miocárdico em ratos

FUNDAMENTO: Treinamento físico (TF) aumenta a sensibilidade dos hormônios tireoidianos (HT) e a expressão gênica de estruturas moleculares envolvidas no movimento intracelular de cálcio do miocárdio, enquanto a restrição alimentar (RIA) promove efeitos contrários ao TF. OBJETIVO: Avaliar os efeitos da associação TF e RIA sobre os níveis plasmáticos dos HT e a produção de mRNA dos receptores HT e estruturas moleculares do movimento de cálcio do miocárdio de ratos. MÉTODOS: Utilizaram-se ratos Wistar Kyoto divididos em: controle (C, n = 7), RIA (R50, n = 7), exercício físico (EX, n = 7) e exercício físico + RIA (EX50, n = 7). A RIA foi de 50% e o TF foi natação (1 hora/dia, cinco sessões/semana, 12 semanas consecutivas). Avaliaram-se as concentrações séricas de triiodotironina (T3), tiroxina (T4) e hormônio tireotrófico (TSH). O mRNA da bomba de cálcio do retículo sarcoplasmático (SERCA2a), fosfolamban (PLB), trocador Na+/Ca+2 (NCX), canal lento de cálcio (canal-L), rianodina (RYR), calsequestrina (CQS) e receptor de HT (TRα1 e TRβ1) do miocárdio foram avaliados por reação em cadeia da polimerase (PCR) em tempo real. RESULTADOS: RIA reduziu o T4, TSH e mRNA do TRα1 e aumentou a expressão da PLB, NCX e canal-L. TF aumentou a expressão do TRβ1, canal-L e NCX. A associação TF e RIA reduziu T4 e TSH e aumentou o mRNA do TRβ1, SERCA2a, NCX, PLB e correlação do TRβ1 com a CQS e NCX. CONCLUSÃO: Associação TF e RIA aumentou o mRNA das estruturas moleculares cálcio transiente, porém o eixo HT-receptor não parece participar da transcrição gênica dessas estruturas.

IL-4 and IL-13 inhibit IL-1β and TNF-α induced kinin B 1 and B2 receptors through a STAT6-dependent mechanism

Background and Purpose Bone resorption induced by interleukin-1β (IL-1β) and tumour necrosis factor (TNF-α) is synergistically potentiated by kinins, partially due to enhanced kinin receptor expression. Inflammation-induced bone resorption can be impaired by IL-4 and IL-13. The aim was to investigate if expression of B1 and B2 kinin receptors can be affected by IL-4 and IL-13. Experimental Approach We examined effects in a human osteoblastic cell line (MG-63), primary human gingival fibroblasts and mouse bones by IL-4 and IL-13 on mRNA and protein expression of the B1 and B2 kinin receptors. We also examined the role of STAT6 by RNA interference and using Stat6-/- mice. Key Results IL-4 and IL-13 decreased the mRNA expression of B1 and B2 kinin receptors induced by either IL-1β or TNF-α in MG-63 cells, intact mouse calvarial bones or primary human gingival fibroblasts. The burst of intracellular calcium induced by either bradykinin (B2 agonist) or des-Arg10-Lys-bradykinin (B1 agonist) in gingival fibroblasts pretreated with IL-1β was impaired by IL-4. Similarly, the increased binding of B1 and B2 ligands induced by IL-1β was decreased by IL-4. In calvarial bones from Stat6-deficient mice, and in fibroblasts in which STAT6 was knocked down by siRNA, the effect of IL-4 was decreased. Conclusions and Implications These data show, for the first time, that IL-4 and IL-13 decrease kinin receptors in a STAT6-dependent mechanism, which can be one important mechanism by which these cytokines exert their anti-inflammatory effects and impair bone resorption. © 2013 The Authors. British Journal of Pharmacology © 2013 The British Pharmacological Society.

Avaliação da função miocárdia de ratos obesos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influência da obesidade sobre a expressão gênica das proteínas reguladoras do trânsito de cálcio miocárdico

Pós-graduação em Fisiopatologia em Clínica Médica - FMB

Efeito da apocinina na hipertensão, disfunção endotelial e hipertrofia ventricular esquerda em Ratos Espontaneamente Hipertensos (SHR)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito de diferentes doses de hormônios tireoidianos sobre a expressão gênica e protéica de proteínas relacionadas ao trânsito de cálcio em animais obesos e obesos submetidos à restrição alimentar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência do antioxidante quercetina sobre a remodelação cardíaca e a atividade oxidativa de ratos com Diabetes mellitus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mecanismos envolvidos na cardiotoxidade aguda induzida pela doxorrubicina em ratos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Investigação de agonismo tendencioso em α1A- e α1B-adrenoceptores

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A influência da ativação oocitária artificial com ionóforo de cálcio A23187 em pacientes submetidos a ciclos de injeção intracitoplasmática utilizando diferentes origens de espermatozóides

Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB