RESUMO
OBJECTIVES: To achieve a more beautiful and younger appearance, reducing wrinkles is a key concern. The process of wrinkle formation is complex and the development of truly effective cosmetic ingredients to reduce wrinkles remains a challenge. Recent studies have revealed a close relationship between wrinkles and skin thinning, suggesting that preventing skin thinning could also prevent wrinkle formation. In this study, we examined the role of extracellular adenosine triphosphate (eATP) in the progression of thinning, as eATP reportedly increases skin ageing factors, such as senescence-associated secreted phenotype (SASP) factors in epidermal cells. We determined the effects of Mentha piperita leaf extract on suppressing eATP to reduce thinning and wrinkles. METHODS: Adenosine triphosphate (ATP) levels were measured in normal human epidermal keratinocytes (NHEK) in the presence of M. piperita leaf extract. Dryness, high pH, and UVB radiation were used as extrinsic ageing factors. Intrinsic skin ageing was evaluated by comparing cells from adults (AD-NHEK) and newborns (NB-NHEK). A placebo-controlled in vivo study was carried out with a formulation containing 1% M. piperita leaf extract. RESULTS: The eATP levels were significantly higher in AD-NHEK compared with that in NB-NHEK cells. M. piperita leaf extract significantly decreased eATP levels in adult cells. Extrinsic ageing factors increased eATP levels in NHEK, whereas M. piperita leaf extract significantly suppressed eATP under all conditions. The active components of M. piperita leaf extract, luteolin glucuronide and rosmarinic acid, also decreased eATP. Moreover, compared with placebo lotion, M. piperita leaf extract-formulated lotion markedly increased dermal thickness and reduced wrinkles associated with crow's feet and the neck area. CONCLUSION: We demonstrated for the first time that M. piperita leaf extract containing rosmarinic acid and luteolin-7-O-glucuronide has the potential to reduce eATP release from epidermal keratinocytes. An increase in eATP was observed not only during inflammation but also during natural ageing. Furthermore, the in vivo experiment revealing that 1% M. piperita leaf extract-containing lotion improved dermal thinning and wrinkles across multiple areas is attributed to the amelioration of dermal thinning. Thus, our data suggest the possibility of a novel cosmetic approach for reducing skin ageing by reducing eATP-mediated dermal thinning.
OBJECTIFS: Pour obtenir une apparence plus belle et plus jeune, réduire les rides est une préoccupation clé. Le processus de formation des rides est complexe et le développement d'ingrédients cosmétiques réellement efficaces pour réduire les rides reste un défi. Des études récentes ont révélé une relation étroite entre les rides et l'amincissement de la peau, suggérant que la prévention de l'amincissement de la peau pourrait également prévenir la formation de rides. Dans cette étude, nous avons examiné le rôle de l'adénosine triphosphate extracellulaire (eATP) dans la progression de l'amincissement, car l'eATP augmente apparemment les facteurs de vieillissement de la peau, tels que les facteurs du phénotype sécrétoire associé à la sénescence (SASP) dans les cellules épidermiques. Nous avons déterminé les effets de l'extrait de feuille de Mentha piperita sur la suppression de l'eATP pour réduire l'amincissement et les rides. MÉTHODES: Les niveaux d'adénosine triphosphate (ATP) ont été mesurés dans les kératinocytes épidermiques humains normaux (NHEK) en présence d'extrait de feuille de M. piperita. La sécheresse, le pH élevé et les radiations UVB ont été utilisés comme facteurs de vieillissement extrinsèque. Le vieillissement intrinsèque de la peau a été évalué en comparant les cellules des adultes (ADNHEK) et des nouveaunés (NBNHEK). Une étude in vivo contrôlée par placebo a été réalisée avec une formulation contenant 1% d'extrait de feuille de M. piperita. RÉSULTATS: Les niveaux d'eATP étaient significativement plus élevés dans les ADNHEK comparés à ceux des cellules NBNHEK. L'extrait de feuille de M. piperita a significativement diminué les niveaux d'eATP dans les cellules adultes. Les facteurs de vieillissement extrinsèque ont augmenté les niveaux d'eATP dans les NHEK, tandis que l'extrait de feuille de M. piperita a significativement supprimé l'eATP dans toutes les conditions. Les composants actifs de l'extrait de feuille de M. piperita, la lutéoline glucuronide et l'acide rosmarinique, ont également diminué l'eATP. De plus, comparée à la lotion placebo, la lotion formulée avec de l'extrait de feuille de M. piperita a considérablement augmenté l'épaisseur dermique et réduit les rides associées aux pattes d'oie et à la région du cou. CONCLUSION: Nous avons démontré pour la première fois que l'extrait de feuille de M. piperita contenant de l'acide rosmarinique et de la lutéoline7Oglucuronide a le potentiel de réduire la libération d'eATP des kératinocytes épidermiques. Une augmentation de l'eATP a été observée non seulement pendant l'inflammation mais aussi pendant le vieillissement naturel. En outre, l'expérience in vivo révélant que la lotion contenant 1% d'extrait de feuille de M. piperita a amélioré l'amincissement dermique et les rides sur plusieurs zones est attribuée à l'amélioration de l'amincissement dermique. Ainsi, nos données suggèrent la possibilité d'une nouvelle approche cosmétique pour réduire le vieillissement de la peau en réduisant l'amincissement dermique médié par l'eATP.
RESUMO
GPNMB is involved in multiple cellular functions including cell adhesion, stress protection and stem cell maintenance. In skin, melanocyte-GPNMB is suggested to mediate pigmentation through melanosome formation, but details of keratinocyte-GPNMB have yet to be well understood. We confirmed the expression of GPNMB in normal human epidermal keratinocytes (NHEKs) by reducing the expression using siRNA. A higher calcium concentration of over 1.25 mM decreased the GPNMB expression. Histological staining showed that GPNMB was expressed in the basal layer of normal skins but completely absent in vitiligo skins. The normal expression of GPNMB in nevus depigmentosus skin suggested that lack of GPNMB is characteristic of vitiligo lesional skins. IFN-γ and IL-17A, two cytokines with possible causal roles in vitiligo development, inhibited GPNMB expression in vitro. Approximately 4-8% of the total GPNMB expressed on NHEKs were released possibly by ADAM 10 as a soluble form, but the process of release was not affected by the cytokines. The suppressive effect of IFN-γ on GPNMB was partially via IFN-γ/JAK2/STAT1 signaling axis. Decreased GPNMB expression in keratinocytes may affect melanocyte maintenance or survival against oxidative stress although further studies are needed. These findings indicate a new target for vitiligo treatment, focusing on the novel role of IFN-γ and IL-17 in downregulating keratinocyte-GPNMB.
Assuntos
Regulação da Expressão Gênica , Queratinócitos/metabolismo , Glicoproteínas de Membrana/genética , Vitiligo/genética , Proteínas ADAM/antagonistas & inibidores , Proteínas ADAM/metabolismo , Cálcio/metabolismo , Adesão Celular , Citocinas/metabolismo , Epiderme/metabolismo , Epiderme/patologia , Humanos , Janus Quinase 2/metabolismo , Glicoproteínas de Membrana/metabolismo , Fator de Transcrição STAT1/metabolismo , Transdução de Sinais , Vitiligo/metabolismo , Vitiligo/patologiaRESUMO
(Pro)renin receptor [(P)RR] has been implicated in diverse biological processes through binding to its ligands, which include renin, prorenin, Wnt signaling molecules and subunits of vascular H+-ATPase. Recent studies have reported that (P)RR is implicated in pathophysiological conditions including retinopathy and pancreatic ductal adenocarcinoma, and the soluble form of this receptor [s(P)RR] is considered as a useful biomarker for diseases. The present study examined the effect of aliskiren, the first orally active direct renin inhibitor, on the protein levels of (P)RR using cultured human umbilical vein endothelial cells (HUVECs). The cells were treated with or without aliskiren (10 nM) at 37°C for different durations (0, 8, 16 and 24 h). Aliskiren-treated HUVECs exhibited reduced proliferation compared with those treated without the drug. Furthermore, aliskiren treatment decreased not only the level of exogenous prorenin that bound to the membranes of HUVECs, but also the renin activity derived from this binding activity. These results indicate that the quantity of full-length (P)RR was reduced by aliskiren treatment, and furthermore, that the level of s(P)RR released from HUVECs was decreased with the treatment. Recent study has reported that s(P)RR exerted antidiuretic function. The current study suggests that the levels of s(P)RR, as a potential antidiuretic molecule and prospective disease biomarker, may be decreased during anti-hypertensive treatments with aliskiren.
RESUMO
BACKGROUND: Angiotensinogen (ANG) is a macromolecular precursor of angiotensin, which regulates blood pressure and electrolyte balance. ANG is specifically cleaved by renin, an aspartic protease, to initiate the angiotensin-processing cascade. Ovine ANG (oANG) from sheep plasma has been shown to be a better substrate for human renin, and it has been used in clinical renin assays. To expand the availability of oANG, we aimed to produce milligram levels of recombinant oANG using an Escherichia coli expression system. RESULTS: When recombinant oANG was expressed from a T7 promoter in various E. coli strains at 37 °C, it accumulated in the insoluble fraction. However, by expressing oANG at 37 °C from a tac promoter, which has weaker transcriptional activity than a T7 promoter, we significantly elevated the ratio of soluble to insoluble recombinant oANG. Using a novel culturing system and auto-induction culture medium, we purified tac-expressed recombinant oANG to homogeneity, with a yield of 4.0 mg per liter of culture. Based on size-exclusion gel filtration analysis and dynamic light scattering analysis, the resulting purified oANG is a monomer in solution. The circular dichroism spectrum of E. coli-expressed recombinant oANG was similar to that of oANG expressed in CHO cells. Differential scanning fluorimetry showed that both preparations undergo a two-state transition during thermal denaturation, and the melting temperatures of recombinant oANG expressed in E. coli and CHO cells were 49.4 ± 0.16 °C and 51.6 ± 0.19 °C, respectively. The K(m) values of both oANG preparations were similar; the k(cat) value of E. coli-expressed recombinant oANG was slightly higher than that of CHO-expressed oANG. CONCLUSIONS: Recombinant oANG expressed in E. coli functions as a human renin substrate. This study presents an E. coli-based system for the rapid production of milligram quantities of a human renin substrate, which will be useful for both fundamental and clinical studies on renin and hypertension.
Assuntos
Angiotensinogênio/metabolismo , Escherichia coli/genética , Proteínas Recombinantes/metabolismo , Renina/metabolismo , Angiotensinogênio/química , Angiotensinogênio/genética , Angiotensinogênio/isolamento & purificação , Animais , Cinética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Renina/química , OvinosRESUMO
Binding properties of acid-activated prorenin to (pro)renin receptor [(P)RR] was investigated in vitro to discuss possible roles of such reversibly acid-activated prorenin in the renin angiotensin (RA) system. Prorenin was acidified at pH 3.3, 4.5, 5.5, 6.5, and its activation level was measured at 1, 2, 4, 8, 12, and 25 h. Prorenin, activated non-proteolytically in time- and pH-dependent manners, was verified by Western blot analyses. Acidification of prorenin for 25 h at pH 3.3, 4.5, 5.5, and 6.5 showed 78%, 54%, 34%, and 20% activities, respectively when compared with the renin activity of trypsinized prorenin as 100%. Additionally, the binding properties of acidified prorenin to (P)RR were elucidated both at the equilibrium state and in the kinetic state using BIAcore. BIAcore assay showed that acidified prorenin at pH 3.3, 4.5, 5.5, and 6.5 had apparent K(D) of 1.57 × 10(4), 14.1, 8.29, and 8.04 nM, respectively while native prorenin at pH 7.4 had a K(D) of 7.8 nM. At equilibrium state, K(D) of native prorenin was 1.42 nM whereas apparent K(D) varied from 1.25 to 5.0 nM for the prorenin acidified at pH 4.5, 5.5, and 6.5. The K(m) values of free forms of acidified prorenin at different pH (0.33-0.5 µM) was almost similar to those of (P)RR-bound forms of acidified prorenin (0.5-0.77 µM). These in vitro data indicate that prorenin acidified in vivo possibly modulate RA system in receptor-dependent and/or -independent manners which could ultimately lead to the pathogenesis of diseases.
Assuntos
Ácidos/química , Receptores de Superfície Celular/química , Renina/química , Animais , Células CHO , Cricetinae , Humanos , Concentração de Íons de Hidrogênio , Proteínas Imobilizadas , Cinética , Ligação Proteica , Proteínas Recombinantes/química , Ressonância de Plasmônio de Superfície , Receptor de Pró-ReninaRESUMO
Before discovery of (pro)renin receptor, prorenin was regarded as a source of renin and probable diagnostic marker for diabetic nephropathy/Wilms' tumor. It is now considered that prorenin can perform renin activity by binding to (P)RR and binding mechanism of (pro)renin to (P)RR was indicated in many in vitro studies. Considering the physiological importance and pathological involvement of (P)RR, it is indeed a demand of time to determine the three dimensional structure of (P)RR to design (P)RR blocker(s) effective for (pro)renin. It may also facilitate to explain the incompatible data about the effective application of decoy peptide as (P)RR blocker. So far, studies have discussed the bindings of (pro)renin to (P)RR using peptides mimicking the structures of ligands (e.g., the decoy including "handle" region peptide, the "hinge" peptide etc). In this review, the binding mechanism of ligands has been highlighted from the structural aspect of (P)RR using several anti-(P)RR antibodies designed from the primary structure of (pro)renin receptor. Therefore, this review would give us a clue regarding the plausible binding region(s) for prorenin in the (P)RR.
Assuntos
Receptores de Superfície Celular/metabolismo , Renina/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Humanos , Cinética , Dados de Sequência Molecular , Domínios e Motivos de Interação entre Proteínas , Receptores de Superfície Celular/química , Receptores de Superfície Celular/genética , Renina/química , Renina/genética , Receptor de Pró-ReninaRESUMO
A 30-kDa protein in the medium of cultured human umbilical vein endothelial cells (HUVECs) was identified as (pro)renin receptor, (P)RR, by western blot analysis using anti-human (P)RR antibodies. The protein bound recombinant human prorenin with a K(D) of 4.0 nmol l(-1) and activated prorenin. These observations suggest the presence of soluble (P)RR, s(P)RR, in the medium of cultured HUVECs. For quantification of the s(P)RR in the medium, an enzyme-linked immunosorbent assay (ELISA) was established. The quantitative range of the ELISA was validated over a nominal range of 7.5-300 pmol l(-1) in the wells of a microtiter plate. The assay system showed good linearity (r(2)=0.99) with interassay (5.8-9.7%) and intraassay (2.1-7.0%) precision. Using this method, the concentration of s(P)RR in the culture medium of HUVECs was measured to be 32 pmol l(-1). Therefore, these results show qualitative and quantitative evidence that prorenin can be activated after binding to s(P)RR secreted from cultured HUVECs.
Assuntos
Células Endoteliais/metabolismo , Receptores de Superfície Celular/análise , Células Cultivadas , Meios de Cultura , Ensaio de Imunoadsorção Enzimática , Humanos , Receptores de Superfície Celular/metabolismo , Renina/metabolismo , Veias Umbilicais/citologia , Veias Umbilicais/metabolismo , Receptor de Pró-ReninaRESUMO
Human (pro)renin receptor ((P)RR) has been implicated in the augmentation of many biological and cellular processes through bindings to its ligands, renin and prorenin. In this study, we investigated the effects of aliskiren, a direct oral renin inhibitor, on the activities of free and (P)RR-bound forms of human mature renin. We also elucidated the effect of aliskiren on the 'renin activity' of the receptor-bound form of prorenin. Aliskiren had an IC(50) of 0.72 nmol l(-1) against renin. The compound competitively inhibited renin activity with an inhibitory constant (K(i)) of 0.18 nmol l(-1). Furthermore, the dissociation constants (K(D)) for aliskiren from renin and prorenin bound to (P)RR were determined using surface plasmon resonance in a BIAcore assay system (Uppsala, Sweden). These values were estimated to be 0.46 ± 0.03 and 0.25 ± 0.01 nmol l(-1), respectively. The compound competitively inhibited the renin activities of (P)RR-bound forms of both renin and prorenin with a K(i) of 0.14 and 0.15 nmol l(-1), respectively. These results indicate that aliskiren could be a potent inhibitor of the free forms of mature renin and of the receptor-bound forms of renin and prorenin.
Assuntos
Amidas/metabolismo , Fumaratos/metabolismo , Receptores de Superfície Celular/metabolismo , Renina/metabolismo , ATPases Vacuolares Próton-Translocadoras/metabolismo , Amidas/farmacologia , Fumaratos/farmacologia , Humanos , Técnicas In Vitro , Ligantes , Ligação Proteica , Receptores de Superfície Celular/efeitos dos fármacos , Renina/antagonistas & inibidores , Fatores de Tempo , ATPases Vacuolares Próton-Translocadoras/efeitos dos fármacos , Receptor de Pró-ReninaRESUMO
Decoy peptide (R10PIFLKRMPSI19P) showed its beneficial role in ameliorating the end-stage organ damage related disorders. Subsequently, in vivo and in vitro studies have been carried out to verify its effectiveness in several models using different experimental approaches. These studies with decoy peptide including the "handle" sequence have focused on the association of the (pro)renin receptor and prorenin in the pathogenesis of diabetes and hypertension. However, the function of (pro)renin receptor might be more complex than it was anticipated as it is not only distributed intracellularly and appeared on the cell membrane but also found in plasma. The decoy resembling the N-terminal sequence of prorenin has been useful in determining the structure-function relationship of prorenin and (P)RR. Therefore, this review tries to shed light on the use of decoy peptide in elucidating the functional properties of both prorenin and (pro)renin receptor by pointing out recent studies.
Assuntos
Oligopeptídeos/fisiologia , Sequência de Aminoácidos , Animais , Humanos , Dados de Sequência Molecular , Oligopeptídeos/química , Ratos , Ratos Endogâmicos SHRRESUMO
In this study, binding properties of human prorenin to rat (pro)renin receptor (r(P)RR) and rat prorenin to human (pro)renin receptor (h(P)RR) were elucidated in vitro to investigate species specificity of prorenin bindings to (P)RR. Both (P)RRs were expressed in vitro based on wheat germ lysate and purified using His trap column. The association and dissociation rate constants of human and rat prorenin for the immobilized r(P)RR and h(P)RR were 6.64 x 10(6) and 1.01 x 10(6) M-1.s-1 and, 0.024 and 8.45 x 10(-3) s-1, respectively. Their KD values were 3.7 nM (3-fold higher than that of human prorenin vs h(P)RR (1.2 nM)) and 8.3 nM (1.2-fold lower than that of rat prorenin vs r(P)RR (10.2 nM)), respectively. Additionally, human and rat prorenin bound to the pre-adsorbed rat and human (P)RR, respectively, performed enzymatic activities. Their molecular activities were 4.1h-1 (almost similar (3.8h -1) to human prorenin vs h(P)RR) and 0.98 h-1 (approximately 2-fold lower than rat prorenin vs r(P)RR), respectively. Thus, these results suggest the species specificity for bindings of prorenin to (P)RR, which could be useful in elucidating the biochemical properties of prorenin binding to the receptor.
Assuntos
Receptores de Superfície Celular/metabolismo , Renina/metabolismo , Animais , Sequência de Bases , Células CHO , Células COS , Chlorocebus aethiops , Cricetinae , Cricetulus , Primers do DNA , Humanos , Ligação Proteica , Ratos , Proteínas Recombinantes/metabolismo , Especificidade da Espécie , Receptor de Pró-ReninaRESUMO
The economic burden resulting from diabetic foot consumes a major portion of resources. The study was undertaken to assess the cost-effectiveness of medical intervention in patients with diabetic foot. At baseline 906 patients were analyzed. Then 200 patients with diabetic foot were purposively selected from a tertiary diabetes care hospital. Of these, 100 were late in detection and poorly managed (late diabetic foot or LDF) and 100 were detected early and properly managed (early diabetic foot or EDF). Among 906 patients, 2.8% (25 patients) were found to develop diabetic foot. Total cost of treatment was US$13,308.16 with an average of US$443.60 per patient. Comparing the cost of patients who underwent amputation with the patients who are not yet amputated, cost difference was US$6657.74. The result showed that cost of amputation was 5.54 times higher than the usual treatment. The average cost of care was US$134 per patient. Among the average annual cost, LDF consumed US$18,918. Fifty percent of the costs were attributable to drugs for both groups of which 77% was for LDF and 29% to hospitalizations. The regression equation showed that medical cost is significantly related to complications. Proper management can substantially reduce the cost of care of patients with diabetic foot.
Assuntos
Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/economia , Pé Diabético/diagnóstico , Pé Diabético/economia , Pé Diabético/terapia , Amputação Cirúrgica/economia , Bangladesh , Estudos de Casos e Controles , Quimioprevenção/economia , Estudos de Coortes , Efeitos Psicossociais da Doença , Análise Custo-Benefício , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/terapia , Pé Diabético/epidemiologia , Diagnóstico Precoce , Feminino , Hospitalização/economia , Hospitais , Humanos , Masculino , Prevalência , Estudos Retrospectivos , Fatores de Tempo , Resultado do TratamentoRESUMO
An important role of the decoy peptide sequence has recently been suggested in vitro for the binding of prorenin to the (pro)renin receptor [PRR]. In this study, other prospective crucial regions in renin and prorenin responsible for their interaction with PRR were investigated using various kinds of peptides, e.g., the "hinge" S149QGVLKEDVF158 designed from the structure of renin also common to prorenin, L1PPTDTTTF8P, L1PPTDTTTFKRIFLKR15P and the decoy (R10PIFLKRMPSI19P) designed from the predicted structure of prorenin. For the kinetic analysis, the recombinant hPRR was immobilized on the biosensor surface through a specific anti-PRR antibody. In case of the equilibrium state analysis, the PRR was directly adsorbed on plastic wells for observing the bindings of renin/prorenin. The dissociation constants (KD) for the bindings of renin and prorenin to the pre-adsorbed receptors were 4.5 and 1.0 nM, respectively, similar to those stated in the kinetic study by BIAcore assay. The "hinge" region peptide bound to PRR in a dose-dependent manner with a KD estimated 17.0 nM which was five times higher than that of the decoy. The KD values for L1PPTDTTTF8P and L1PPTDTTTFKRIFLKR15P were 52 and 7.6 nM, respectively. The "hinge" peptide, as the decoy, inhibited the bindings of renin and prorenin to PRR. The inhibition constant (Ki) for the binding of renin and prorenin by the decoy and "hinge" were 16.7 and 15.1, and 37.1 and 30.7 nM, respectively. These in vitro studies suggest that renin has a single and prorenin has at least two high affinity binding sites for the PRR.
Assuntos
Receptores de Superfície Celular/química , Receptores de Superfície Celular/metabolismo , Renina/química , Renina/metabolismo , Sequência de Aminoácidos , Sítios de Ligação/genética , Humanos , Técnicas In Vitro , Cinética , Modelos Biológicos , Modelos Moleculares , Dados de Sequência Molecular , Oligopeptídeos/química , Oligopeptídeos/genética , Oligopeptídeos/metabolismo , Conformação Proteica , Receptores de Superfície Celular/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Renina/genética , Receptor de Pró-ReninaRESUMO
This study investigated a role of decoy peptide region (R10PIFLKRMPSI19P) in prorenin prosegment for prorenin binding to the (pro)renin receptor using the surface plasmon resonance technique. Three kinds of anti-receptor antibodies labeled as anti-107/121, anti-221/235 and anti-His tag antibody were prepared. The respective antigens D107SVANSIHSLFSEET121 (close to the N-terminal side of receptor), E221IGKRYGEDSEQFRD235 (N-terminal side of the transmembrane part of receptor) and 10xHis sequence (C-terminus) were designed based on the sequence of the receptor. These antibodies were immobilized on the CM5 sensor chip by amine coupling and allowed to bind to the receptor. Human prorenin, renin and the decoy bound to the receptor associated with antibodies. Their association (ka) and dissociation (kd) rate constants were measured and the dissociation constants (KD) were determined using Langmuir 1:1 kinetic binding model. The KD for interaction of prorenin and receptor associated to anti-107/121, anti-221/235 and anti-His tag antibodies were 2.9, 1.2 and 7.8 nM, respectively and for renin they were 9.3, 4.4 and 7.1 nM. The decoy bound to the respective immobilized receptor-antibody complexes at KD's of 6.2, 3.5 and 15.2 nM. Prorenin, renin and decoy had lower KD at the nanomolar ranges compared to those of L1PPTD4P in the prorenin prosegment and A248KKRLFDYVV257 in the C-domain of mature renin. The decoy reduced the binding of not only prorenin but also renin to (P)RR. These data are direct evidence that prorenin, renin and the peptides bind to (P)RR and the decoy reduces prorenin binding, supporting our hypothesis that decoy peptide region has a crucial role in prorenin binding.
Assuntos
Oligopeptídeos/metabolismo , Receptores de Superfície Celular/metabolismo , Renina/metabolismo , Sequência de Aminoácidos , Animais , Anticorpos/química , Linhagem Celular , Humanos , Cinética , Dados de Sequência Molecular , Oligopeptídeos/química , Oligopeptídeos/imunologia , Ligação Proteica , Receptores de Superfície Celular/química , Receptores de Superfície Celular/imunologia , Renina/química , Ressonância de Plasmônio de Superfície , Receptor de Pró-ReninaRESUMO
To investigate gender differences, if any, in leptin concentrations from umbilical cord blood of new born infants of mothers with type 2 diabetes mellitus (DM), gestational diabetes mellitus (GDM), and Non diabetic (ND) at delivery. Serum leptin concentrations were measured in 105 newborns (53 males and 52 females in the three groups). Blood was taken from the umbilical cord of the babies at delivery. Maternal anthropometric measurements were recorded within 48 hours after delivery. Pearson correlation coefficient was used to explore the relationship between serum leptin concentrations and anthropometric measures of the fetus and their mother. Both Serum leptin level and serum C-peptide was measured by chemiluminescence based ELISA. The median range of leptin concentration in cord blood was ND group: Male [13.91 (3.22 - 47.63)], Female [16.88 (2 - 43.65)]; GDM group: Male [32 (7 - 76.00)], Female [36.73 (4.80 - 81.20)]; DM group: Male [20.90 (2 -76.00)], Female [32 {2.58 - 80.67)]. Cord serum leptin levels correlated with birth weight(r=0.587, p=0.0001), ponderal index (PI) (r=.319, p=0.024)of the babies and body mass index (BMI) (r=-0.299, p=0.035) of their mothers but did not correlate with gestational age, cord serum C-peptide concentration or placental weight at delivery. Leptin concentrations were higher in the female fetus in comparison to the male fetus. Birth weight of the female fetuses were also higher than that of male fetus. We found that there are very strong associations between cord leptin concentrations at delivery and birth weight, ponderal index of the baby, body mass index of the mothers with Type 2 DM. We also found that high leptin levels could represent an important feedback modulator of substrate supply and subsequently for adipose tissue status during late gestation or adipose tissue is the major determinant of circulating leptin levels.
RESUMO
BACKGROUND: The relative contribution of insulin secretion and sensitivity in the development of type 2 diabetes mellitus (T2DM) vary from population to population due to the heterogeneous nature of the disease. The study was undertaken to evaluate the insulin secretory capacity and sensitivity in a Bangladeshi type 2 diabetic population and to explore the association of some of the anthropometric (BMI, WHR, MBP) and biochemical factors (glucose, lipids, HbA(1c)) known to modulate B-cell function and insulin action. METHODS: Ninety three T2DM and 70 age-matched control subjects were studied for their fasting glucose, lipids, HbA(1c) (by HPLC) and C-peptide (by ELISA). Insulin secretion (HOMA B) and insulin sensitivity (HOMA S) were calculated by homeostasis model assessment (HOMA). RESULTS: Both insulin secretion and sensitivity were significantly reduced in diabetic as compared to control subjects (HOMA B%, geometric M +/- SD, 34.67 +/- 1.73 vs 104.71 +/- 1.34, p < 0.001; HOMA S%, 67.60 +/- 1.69 vs 85.11 +/- 1.54, p < 0.01). However, the discriminant function coefficient for HOMA B (1.142) was about 1.5 times higher than that for HOMA S (0.731). In T2DM, HOMA B had positive correlation with BMI (r = 0.362, p < 0.001) and inverse correlation with plasma glucose (r = - 0.701, p < 0.001) and HbA1c (r = - 0.612, p < 0.001). HOMA S was inversely correlated to BMI (r = - 0.274, p < 0.01), WHR (r = - 0.252, p < 0.05), plasma total cholesterol (r = - 0.240, p < 0.05) and triglycerides (r = 0.301, p < 0.01). CONCLUSIONS: Both insulin secretory dysfunction and insulin resistance are present in Bangladeshi T2DM subjects, but B-cell dysfunction seems to be the predominant defect. BMI, plasma glucose and insulin are the major determinants of insulin secretory capacity; and generalized as well as central obesity, plasma glucose, total cholesterol, triglycerides and insulin are among the major determinants of insulin sensitivity in this population.
RESUMO
Since conflicting results have been reported on non-specific immune response in type 1 diabetes, this study evaluates polymorphonuclear neutrophil (PMN) functions in the infection free Long Evan diabetic rats (type 1) by using tests that include: polarization assay, phagocytosis of baker\'s yeasts (Saccharomyces cerevisiae) and nitroblue tetrazolium (NBT) dye reduction. Polarization assay showed that neutrophils from diabetic rats were significantly activated at the basal level compared to those from the controls (p < 0.001). After PMN activation with N-formylmethionyl-leucyl-phenylalanine (FMLP), control neutrophils were found to be more polarized than those of the diabetic neutrophils and the highest proportions of polarization were found to be 67 % and 57 % at 10(-7) M FMLP, respectively. In the resting state, neutrophils from the diabetic rats reduced significantly more NBT dye than that of the controls (p < 0.001). The percentages of phagocytosis of opsonized yeast cells by the neutrophils from control and diabetic rats were 87 % and 61 %, respectively and the difference was statistically significant (p < 0.001). Evaluation of the phagocytic efficiency of PMNs revealed that control neutrophils could phagocytose 381 +/- 17 whereas those from the diabetic rats phagocytosed 282 +/- 16 yeast cells, and the efficiency of phagocytosis varied significantly (p < 0.001). Further, both the percentages of phagocytosis and the efficiency of phagocytosis by the diabetic neutrophils were inversely related with the levels of their corresponding plasma glucose (p = 0.02; r = -0.498 and p < 0.05; r = -0.43, respectively), which indicated that increased plasma glucose reduced the phagocytic ability of neutrophils. Such relationship was not observed with the control neutrophils. These data clearly indicate that PMN functions are altered in the streptozotocin (STZ)-induced diabetic rats, and hyperglycemia may be the cause for the impairment of their functions leading to many infectious episodes.