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1.
Nature ; 584(7821): 479-483, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32788728

RESUMO

Lipopolysaccharide (LPS) resides in the outer membrane of Gram-negative bacteria where it is responsible for barrier function1,2. LPS can cause death as a result of septic shock, and its lipid A core is the target of polymyxin antibiotics3,4. Despite the clinical importance of polymyxins and the emergence of multidrug resistant strains5, our understanding of the bacterial factors that regulate LPS biogenesis is incomplete. Here we characterize the inner membrane protein PbgA and report that its depletion attenuates the virulence of Escherichia coli by reducing levels of LPS and outer membrane integrity. In contrast to previous claims that PbgA functions as a cardiolipin transporter6-9, our structural analyses and physiological studies identify a lipid A-binding motif along the periplasmic leaflet of the inner membrane. Synthetic PbgA-derived peptides selectively bind to LPS in vitro and inhibit the growth of diverse Gram-negative bacteria, including polymyxin-resistant strains. Proteomic, genetic and pharmacological experiments uncover a model in which direct periplasmic sensing of LPS by PbgA coordinates the biosynthesis of lipid A by regulating the stability of LpxC, a key cytoplasmic biosynthetic enzyme10-12. In summary, we find that PbgA has an unexpected but essential role in the regulation of LPS biogenesis, presents a new structural basis for the selective recognition of lipids, and provides opportunities for future antibiotic discovery.


Assuntos
Membrana Celular/química , Escherichia coli/química , Escherichia coli/patogenicidade , Lipopolissacarídeos/química , Lipopolissacarídeos/metabolismo , Amidoidrolases/química , Amidoidrolases/metabolismo , Motivos de Aminoácidos , Membrana Externa Bacteriana/química , Membrana Externa Bacteriana/metabolismo , Sítios de Ligação , Membrana Celular/metabolismo , Estabilidade Enzimática , Escherichia coli/citologia , Escherichia coli/efeitos dos fármacos , Genes Essenciais , Hidrolases/química , Hidrolases/metabolismo , Lipídeo A/química , Lipídeo A/metabolismo , Lipopolissacarídeos/biossíntese , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Modelos Moleculares , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Periplasma/química , Periplasma/metabolismo , Ligação Proteica , Virulência
2.
PLoS One ; 15(7): e0235784, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32658899

RESUMO

Soft tissue is composed of cells surrounded by an extracellular matrix that is made up of a diverse array of intricately organized proteins. These distinct components work in concert to maintain homeostasis and respond to tissue damage. During tissue repair, extracellular matrix proteins and their degradation products are known to influence physiological processes such as angiogenesis and inflammation. In this study we developed a discovery platform using a decellularized extracellular matrix biomaterial to identify new chemotrophic factors derived from the extracellular matrix. An in vitro culture of RAW.264 macrophage cells with the biomaterial ovine forestomach matrix led to the identification of a novel ~12 kDa chemotactic factor, termed 'MayDay', derived from the N-terminal 31-188 sequence of decorin. The recombinant MayDay protein was shown to be a chemotactic agent for mesenchymal stromal cells in vitro and in vivo. We hypothesize that the macrophage-induced cleavage of decorin, via MMP-12, leads to the release of the chemotactic molecule MayDay, that in turn recruits cells to the site of damaged tissue.


Assuntos
Fatores Quimiotáticos/farmacologia , Decorina/farmacologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Sequência de Aminoácidos , Animais , Células Cultivadas , Fatores Quimiotáticos/química , Quimiotaxia/efeitos dos fármacos , Decorina/química , Células-Tronco Mesenquimais/citologia , Camundongos , Fragmentos de Peptídeos/química , Células RAW 264.7 , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacologia , Ovinos
4.
PLoS One ; 15(5): e0227932, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32469873

RESUMO

BACKGROUND AND OBJECTIVE: For many pathological states, microparticles are supposed to be one of the causes of hypercoagulation. Although there are some indirect data about microparticles participation in coagulation activation and propagation, the integral hemostasis test Thrombodynamics allows to measure micropaticles participation in these two coagulation phases directly. Demonstrates microparticles participation in coagulation activation by influence on the appearance of coagulation centres in the plasma volume and the rate of clot growth from the surface with immobilized tissue factor.Methods: Microparticles were obtained from platelets and erythrocytes by stimulation with thrombin receptor-activating peptide (SFLLRN) and calcium ionophore (A23187), respectively, from monocytes, endothelial HUVEC culture and monocytic THP cell culture by stimulation with lipopolysaccharides. Microparticles were counted by flow cytometry and titrated in microparticle-depleted normal plasma in the Thrombodynamics test. RESULTS: Monocyte microparticles induced the appearance of clotting centres through the TF pathway at concentrations approximately 100-fold lower than platelet and erythrocyte microparticles, which activated plasma by the contact pathway. For endothelial microparticles, both activation pathways were essential, and their activity was intermediate. Monocyte microparticles induced plasma clotting by the appearance of hundreds of clots with an extremely slow growth rate, while erythrocyte microparticles induced the appearance of a few clots with a growth rate similar to that from surface covered with high-density tissue factor. Patterns of clotting induced by platelet and endothelial microparticles were intermediate. Platelet, erythrocyte and endothelial microparticles impacts on the rate of clot growth from the surface with tissue factor did not differ significantly within the 0-200·103/ul range of microparticles concentrations. However, at concentrations greater than 500·103/ul, erythrocyte microparticles increased the stationary clot growth rate to significantly higher levels than do platelet microparticles or artificial phospholipid vesicles consisting of phosphatidylcholine and phosphatidylserine. CONCLUSION: Microparticles of different origins demonstrated qualitatively different characteristics related to coagulation activation and propagation.


Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Micropartículas Derivadas de Células/efeitos dos fármacos , Trombina/metabolismo , Trombose/sangue , Plaquetas/efeitos dos fármacos , Calcimicina/farmacologia , Cálcio/metabolismo , Micropartículas Derivadas de Células/metabolismo , Células Endoteliais/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Citometria de Fluxo , Células Endoteliais da Veia Umbilical Humana , Humanos , Monócitos/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Trombose/tratamento farmacológico , Trombose/patologia
5.
Biochem Pharmacol ; 178: 114057, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32470547

RESUMO

COVID-19 is an ongoing viral pandemic disease that is caused by SARS-CoV2, inducing severe pneumonia in humans. However, several classes of repurposed drugs have been recommended, no specific vaccines or effective therapeutic interventions for COVID-19 are developed till now. Viral dependence on ACE-2, as entry receptors, drove the researchers into RAS impact on COVID-19 pathogenesis. Several evidences have pointed at Neprilysin (NEP) as one of pulmonary RAS components. Considering the protective effect of NEP against pulmonary inflammatory reactions and fibrosis, it is suggested to direct the future efforts towards its potential role in COVID-19 pathophysiology. Thus, the review aimed to shed light on the potential beneficial effects of NEP pathways as a novel target for COVID-19 therapy by summarizing its possible molecular mechanisms. Additional experimental and clinical studies explaining more the relationships between NEP and COVID-19 will greatly benefit in designing the future treatment approaches.


Assuntos
Antivirais/uso terapêutico , Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/prevenção & controle , Reposicionamento de Medicamentos/métodos , Neprilisina/antagonistas & inibidores , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Transdução de Sinais/efeitos dos fármacos , Angiotensina I/farmacologia , Angiotensina I/uso terapêutico , Antagonistas de Receptores de Angiotensina/farmacologia , Antagonistas de Receptores de Angiotensina/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Antivirais/farmacologia , Betacoronavirus/fisiologia , Infecções por Coronavirus/fisiopatologia , Infecções por Coronavirus/virologia , Reposicionamento de Medicamentos/estatística & dados numéricos , Reposicionamento de Medicamentos/tendências , Humanos , Neprilisina/metabolismo , Fragmentos de Peptídeos/farmacologia , Fragmentos de Peptídeos/uso terapêutico , Pneumonia Viral/fisiopatologia , Pneumonia Viral/virologia
6.
Nat Commun ; 11(1): 2070, 2020 04 24.
Artigo em Inglês | MEDLINE | ID: covidwho-116533

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, at the end of 2019, and there are currently no specific antiviral treatments or vaccines available. SARS-CoV-2 has been shown to use the same cell entry receptor as SARS-CoV, angiotensin-converting enzyme 2 (ACE2). In this report, we generate a recombinant protein by connecting the extracellular domain of human ACE2 to the Fc region of the human immunoglobulin IgG1. A fusion protein containing an ACE2 mutant with low catalytic activity is also used in this study. The fusion proteins are then characterized. Both fusion proteins have a high binding affinity for the receptor-binding domains of SARS-CoV and SARS-CoV-2 and exhibit desirable pharmacological properties in mice. Moreover, the fusion proteins neutralize virus pseudotyped with SARS-CoV or SARS-CoV-2 spike proteins in vitro. As these fusion proteins exhibit cross-reactivity against coronaviruses, they have potential applications in the diagnosis, prophylaxis, and treatment of SARS-CoV-2.


Assuntos
Betacoronavirus/efeitos dos fármacos , Fragmentos Fc das Imunoglobulinas/química , Imunoglobulina G/química , Testes de Neutralização , Peptidil Dipeptidase A/química , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/farmacologia , Glicoproteína da Espícula de Coronavírus/antagonistas & inibidores , Animais , Betacoronavirus/metabolismo , Ligação Competitiva/efeitos dos fármacos , Reações Cruzadas , Desenho de Fármacos , Humanos , Fragmentos Fc das Imunoglobulinas/metabolismo , Fragmentos Fc das Imunoglobulinas/farmacologia , Imunoglobulina G/metabolismo , Imunoglobulina G/farmacologia , Técnicas In Vitro , Concentração Inibidora 50 , Fusão de Membrana/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/farmacocinética , Peptidil Dipeptidase A/farmacologia , Domínios Proteicos/genética , Estabilidade Proteica , Receptores Virais/antagonistas & inibidores , Receptores Virais/química , Receptores Virais/genética , Receptores Virais/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/farmacocinética , Vírus da SARS/efeitos dos fármacos , Vírus da SARS/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo
7.
Nat Commun ; 11(1): 2070, 2020 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-32332765

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, at the end of 2019, and there are currently no specific antiviral treatments or vaccines available. SARS-CoV-2 has been shown to use the same cell entry receptor as SARS-CoV, angiotensin-converting enzyme 2 (ACE2). In this report, we generate a recombinant protein by connecting the extracellular domain of human ACE2 to the Fc region of the human immunoglobulin IgG1. A fusion protein containing an ACE2 mutant with low catalytic activity is also used in this study. The fusion proteins are then characterized. Both fusion proteins have a high binding affinity for the receptor-binding domains of SARS-CoV and SARS-CoV-2 and exhibit desirable pharmacological properties in mice. Moreover, the fusion proteins neutralize virus pseudotyped with SARS-CoV or SARS-CoV-2 spike proteins in vitro. As these fusion proteins exhibit cross-reactivity against coronaviruses, they have potential applications in the diagnosis, prophylaxis, and treatment of SARS-CoV-2.


Assuntos
Betacoronavirus/efeitos dos fármacos , Fragmentos Fc das Imunoglobulinas/química , Imunoglobulina G/química , Testes de Neutralização , Peptidil Dipeptidase A/química , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/farmacologia , Glicoproteína da Espícula de Coronavírus/antagonistas & inibidores , Animais , Betacoronavirus/metabolismo , Ligação Competitiva/efeitos dos fármacos , Reações Cruzadas , Desenho de Fármacos , Humanos , Fragmentos Fc das Imunoglobulinas/metabolismo , Fragmentos Fc das Imunoglobulinas/farmacologia , Imunoglobulina G/metabolismo , Imunoglobulina G/farmacologia , Técnicas In Vitro , Concentração Inibidora 50 , Fusão de Membrana/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/farmacocinética , Peptidil Dipeptidase A/farmacologia , Domínios Proteicos/genética , Estabilidade Proteica , Receptores Virais/antagonistas & inibidores , Receptores Virais/química , Receptores Virais/genética , Receptores Virais/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/farmacocinética , Vírus da SARS/efeitos dos fármacos , Vírus da SARS/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo
9.
Biochim Biophys Acta Biomembr ; 1862(6): 183240, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32119862

RESUMO

The IP3 receptor binding protein released with inositol 1,4,5-trisphosphate (IRBIT) plays important roles in the regulation of intracellular Ca2+ signaling and intracellular pH. The mammals express two IRBIT paralogs, i.e., IRBIT1 (encoded by AHCYL1) and IRBIT2 (encoded by AHCYL2). The clawed frog Xenopus laevis oocyte is widely used for biophysical studies on ion channels and transporters. It remains unknown whether endogenous IRBIT is expressed in Xenopus oocytes. Here, we cloned from frog oocyte irbit2.L and irbit2.S, orthologs of mammalian IRBIT2. When over-expressed, the frog IRBITs powerfully stimulate the electrogenic Na+/HCO3- cotransporter NBCe1-B as mouse IRBIT2-V2 does. Expression of an isolated Nt fragment of NBCe1-B containing the IRBIT-binding domain greatly decreases NBCe1-B activity in oocytes, suggesting that the basal activity of NBCe1-B contains a large component derived from the stimulation by endogenous frog IRBIT. The frog IRBITs are highly homologous to the mammalian ones in the carboxyl-terminal region, but varies greatly in the amino-terminal (Nt) appendage. Interestingly, truncation study showed that the Nt appendage of IRBIT1 and the long Nt appendage of IRBIT2-V2 modestly enhance, whereas the short Nt appendage of IRBIT2-V4 greatly inhibits the functional interaction between IRBIT and NBCe1-B. Finally, Ala-substitution of Ser68, a key phosphorylation site in the PEST domain of IRBIT, causes distinct functional consequences depending on the structural context of the Nt appendage in different IRBIT isoforms. We conclude that the Nt appendage of IRBITs is not necessary for, but plays an important regulatory role in the functional interaction between IRBIT and NBCe1-B.


Assuntos
Inositol 1,4,5-Trifosfato/fisiologia , Simportadores de Sódio-Bicarbonato/metabolismo , Animais , Inositol 1,4,5-Trifosfato/metabolismo , Camundongos , Fragmentos de Peptídeos/farmacologia , Ligação Proteica/efeitos dos fármacos , Simportadores de Sódio-Bicarbonato/efeitos dos fármacos , Proteínas de Xenopus/metabolismo , Xenopus laevis
10.
Artigo em Inglês | MEDLINE | ID: mdl-32208925

RESUMO

Phoenixin is a 20-amino acid peptide (PNX-20) cleaved from the small integral membrane protein 20 (SMIM20), with multiple biological roles in mammals. However, its role in nonmammalian vertebrates is poorly understood. This research aimed to determine whether PNX-20 influences feeding and metabolism in zebrafish. The mRNAs encoding SMIM20 and its putative receptor, super conserved receptor expressed in brain 3 (SREB3), are present in both central and peripheral tissues of zebrafish. Immunohistochemical analysis confirmed the presence of PNX-like immunoreactivity in the gut and in zebrafish liver (ZFL) cell line. We also found that short-term fasting (7 days) significantly decreased smim20 mRNA expression in the brain, gut, liver, gonads, and muscle, which suggests a role for PNX-20 in food intake regulation. Indeed, single intraperitoneal injection of 1,000 ng/g body wt PNX-20 reduced feeding in both male and female zebrafish, likely in part by enhancing hypothalamic cart and reducing hypothalamic/gut preproghrelin mRNAs. Furthermore, the present results demonstrated that PNX-20 modulates the expression of genes involved in glucose transport and metabolism in ZFL cells. In general terms, such PNX-induced modulation of gene expression was characterized by the upregulation of glycolytic genes and the downregulation of gluconeogenic genes. A kinetic study of the ATP production rate from both glycolytic and mitochondrial pathways demonstrated that PNX-20-treated ZFL cells exhibited significantly higher ATP production rate associated with glycolysis than control cells. This confirms a positive role for PNX-20 on glycolysis. Together, these results indicate that PNX-20 is an anorexigen with important metabolic roles in zebrafish.


Assuntos
Depressores do Apetite/farmacologia , Ingestão de Alimentos/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Glucose/metabolismo , Glicólise/efeitos dos fármacos , Proteínas de Homeodomínio/farmacologia , Fragmentos de Peptídeos/farmacologia , Proteínas de Peixe-Zebra/farmacologia , Peixe-Zebra/metabolismo , Animais , Regulação do Apetite/efeitos dos fármacos , Linhagem Celular , Feminino , Regulação da Expressão Gênica , Glicólise/genética , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Masculino , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Transdução de Sinais , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
11.
Org Biomol Chem ; 18(10): 1978-1986, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32104826

RESUMO

Development of an intracellular delivery method for functional peptides via cell-penetrating peptides (CPPs) expands peptide use in basic research and therapeutic applications. Although direct conjugation of a functional peptide with a CPP is the simplest method for delivery, this method has not always been reliable. CPPs usually contain several positively charged amino acids that potentially interact non-specifically with negatively charged molecules in cells and subsequently interfere with conjugated functional peptide function. Here we demonstrate a new intracellular delivery method for peptides in which a functional peptide is released from a positively charged CPP via peptide nucleic acids (PNAs). We prepared an 8-mer PNA conjugated to octa-arginine in tandem (PNA1-CPP) and linked its complementary PNA to an autophagy inducing peptide (PNA2-AIP) by solid-phase peptide synthesis. PNA1-CPP and PNA2-AIP formed a 1 : 1 hybrid via PNA1/PNA2 interaction, thereby indirectly but stably connecting the AIP to the CPP. PNA2-AIP was successfully delivered into cells in a hybrid formation-dependent manner and at least some portion of the PNA1-CPP/PNA2-AIP hybrids dissociated into PNA2-AIP and PNA1-CPP inside the cells. Notably, PNA2-AIP delivered to cells induced more autophagy than AIP directly conjugated to CPP (CPP-AIP). Further, the PNA hybrid did not induce significant cell death. These findings indicate that the PNA1/PNA2 hybrid can function as a molecular glue enabling the delivery of functional peptides into cells.


Assuntos
Proteína Beclina-1/farmacologia , Peptídeos Penetradores de Células/metabolismo , Portadores de Fármacos/metabolismo , Fragmentos de Peptídeos/farmacologia , Ácidos Nucleicos Peptídicos/metabolismo , Autofagia/efeitos dos fármacos , Proteína Beclina-1/metabolismo , Proteína Beclina-1/toxicidade , Peptídeos Penetradores de Células/toxicidade , Portadores de Fármacos/toxicidade , Liberação Controlada de Fármacos , Células HeLa , Humanos , Zíper de Leucina , Oligopeptídeos/metabolismo , Oligopeptídeos/toxicidade , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/toxicidade , Ácidos Nucleicos Peptídicos/toxicidade , Ligação Proteica
12.
PLoS One ; 15(2): e0228265, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32012183

RESUMO

Hypertension is considered as one of the most common diseases that affect human beings (both male and female) due to its high prevalence and also extending widely to both industrialize and developing countries. Angiotensin-converting enzyme (ACE) has a significant role in the regulation of blood pressure and ACE inhibition with inhibitory peptides is considered as a major target to prevent hypertension. In the current study, a blood pressure regulating honey protein (MRJP1) was examined to identify the ACE inhibitory peptides. The 3D structure of MRJP1 was predicted by utilizing the threading approach and further optimized by performing molecular dynamics simulation for 30 nanoseconds (ns) to improve the quality factor up to 92.43%. Root mean square deviation and root mean square fluctuations were calculated to evaluate the structural features and observed the fluctuations in the timescale of 30 ns. AHTpin server based on scoring vector machine of regression models, proteolysis and structural characterization approaches were implemented to identify the potential inhibitory peptides. The anti-hypertensive peptides were scrutinized based on the QSAR models of anti-hypertensive activity and the molecular docking analyses were performed to explore the binding affinities and potential interacting residues. The peptide "EALPHVPIFDR" showed the strong binding affinity and higher anti-hypertensive activity along with the global energy of -58.29 and docking score of 9590. The aromatic amino acids especially Tyr was observed as the key residue to design the dietary peptides and drugs like ACE inhibitors.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Simulação por Computador , Glicoproteínas/química , Simulação de Dinâmica Molecular , Fragmentos de Peptídeos/farmacologia , Peptidil Dipeptidase A/metabolismo , Sequência de Aminoácidos , Inibidores da Enzima Conversora de Angiotensina/química , Fragmentos de Peptídeos/química , Peptidil Dipeptidase A/química , Domínios Proteicos
13.
Microvasc Res ; 129: 103986, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32017943

RESUMO

Wet age-related macular degeneration (AMD) and diabetic retinopathy are the leading causes of blindness through increased angiogenesis. Although VEGF-neutralizing proteins provide benefit, inconsistent responses indicate a need for new therapies. We previously identified the Fibulin-7 C-terminal fragment (Fbln7-C) as an angiogenesis inhibitor in vitro. Here we show that Fbln7-C inhibits neovascularization in vivo, in both a model of wet AMD involving choroidal neovascularization (CNV) and diabetic retinopathy involving oxygen-induced ischemic retinopathy. Furthermore, a short peptide sequence from Fbln7-C is responsible for the anti-angiogenic properties of Fbln7-C. Our work suggests Fbln7-C as a therapeutic candidate for wet AMD and ischemic retinopathy.


Assuntos
Inibidores da Angiogênese/farmacologia , Proteínas de Ligação ao Cálcio/farmacologia , Corioide/irrigação sanguínea , Neovascularização de Coroide/prevenção & controle , Fragmentos de Peptídeos/farmacologia , Neovascularização Retiniana/prevenção & controle , Vasos Retinianos/efeitos dos fármacos , Degeneração Macular Exsudativa/prevenção & controle , Animais , Proteínas de Ligação ao Cálcio/síntese química , Proteínas de Ligação ao Cálcio/genética , Neovascularização de Coroide/genética , Neovascularização de Coroide/metabolismo , Neovascularização de Coroide/patologia , Modelos Animais de Doenças , Feminino , Camundongos Endogâmicos C57BL , Fragmentos de Peptídeos/síntese química , Neovascularização Retiniana/genética , Neovascularização Retiniana/metabolismo , Neovascularização Retiniana/patologia , Vasos Retinianos/metabolismo , Vasos Retinianos/patologia , Degeneração Macular Exsudativa/genética , Degeneração Macular Exsudativa/metabolismo , Degeneração Macular Exsudativa/patologia
14.
Invest Ophthalmol Vis Sci ; 61(2): 24, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32068794

RESUMO

Purpose: O-GlcNAcylation of cellular proteins contributes to the pathophysiology of diabetes and evidence supports a role for augmented O-GlcNAcylation in diabetic retinopathy. The aim of this study was to investigate the impact of the renin-angiotensin system on retinal protein O-GlcNAcylation. Methods: Mice fed a high-fat diet were treated chronically with the angiotensin-converting enzyme inhibitor captopril or captopril plus the angiotensin-(1-7) Mas receptor antagonist A779. Western blotting and quantitative polymerase chain reaction were used to analyze retinal homogenates. Similar analyses were performed on lysates from human MIO-M1 retinal Müller cell cultures exposed to media supplemented with angiotensin-(1-7). Culture conditions were manipulated to influence the hexosamine biosynthetic pathway and/or signaling downstream of the Mas receptor. Results: In the retina of mice fed a high-fat diet, captopril attenuated protein O-GlcNAcylation in a manner dependent on Mas receptor activation. In MIO-M1 cells, angiotensin-(1-7) or adenylate cyclase activation were sufficient to enhance cyclic AMP (cAMP) levels and inhibit O-GlcNAcylation. The repressive effect of cAMP on O-GlcNAcylation was dependent on exchange protein activated by cAMP (EPAC), but not protein kinase A, and was recapitulated by a constitutively active variant of the small GTPase Rap1. We provide evidence that cAMP and angiotensin-(1-7) act to suppress O-GlcNAcylation by inhibition of O-GlcNAc transferase (OGT) activity. In cells exposed to an O-GlcNAcase inhibitor or hyperglycemic culture conditions, mitochondrial superoxide levels were elevated; however, angiotensin-(1-7) signaling prevented the effect. Conclusions: Angiotensin-(1-7) inhibits retinal protein O-GlcNAcylation via an EPAC/Rap1/OGT signaling axis.


Assuntos
Angiotensina I/farmacologia , N-Acetilglucosaminiltransferases/metabolismo , Fragmentos de Peptídeos/farmacologia , Retina/metabolismo , Animais , Captopril/farmacologia , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Retinopatia Diabética/metabolismo , Camundongos , Sistema Renina-Angiotensina/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia
15.
J Neurosci ; 40(17): 3320-3331, 2020 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-32060170

RESUMO

Microglial cells are considered as sensors of brain pathology by detecting any sign of brain lesions, infections, or dysfunction and can influence the onset and progression of neurological diseases. They are capable of sensing their neuronal environment via many different signaling molecules, such as neurotransmitters, neurohormones and neuropeptides. The neuropeptide VGF has been associated with many metabolic and neurological disorders. TLQP21 is a VGF-derived peptide and has been shown to signal via C3aR1 and C1qBP receptors. The effect of TLQP21 on microglial functions in health or disease is not known. Studying microglial cells in acute brain slices, we found that TLQP21 impaired metabotropic purinergic signaling. Specifically, it attenuated the ATP-induced activation of a K+ conductance, the UDP-stimulated phagocytic activity, and the ATP-dependent laser lesion-induced process outgrowth. These impairments were reversed by blocking C1qBP, but not C3aR1 receptors. While microglia in brain slices from male mice lack C3aR1 receptors, both receptors are expressed in primary cultured microglia. In addition to the negative impact on purinergic signaling, we found stimulating effects of TLQP21 in cultured microglia, which were mediated by C3aR1 receptors: it directly evoked membrane currents, stimulated basal phagocytic activity, evoked intracellular Ca2+ transient elevations, and served as a chemotactic signal. We conclude that TLQP21 has differential effects on microglia depending on C3aR1 activation or C1qBP-dependent attenuation of purinergic signaling. Thus, TLQP21 can modulate the functional phenotype of microglia, which may have an impact on their function in health and disease.SIGNIFICANCE STATEMENT The neuropeptide VGF and its peptides have been associated with many metabolic and neurological disorders. TLQP21 is a VGF-derived peptide that activates C1qBP receptors, which are expressed by microglia. We show here, for the first time, that TLQP21 impairs P2Y-mediated purinergic signaling and related functions. These include modulation of phagocytic activity and responses to injury. As purinergic signaling is central for microglial actions in the brain, this TLQP21-mediated mechanism might regulate microglial activity in health and disease. We furthermore show that, in addition to C1qBP, functional C3aR1 responses contribute to TLQP21 action on microglia. However, C3aR1 responses were only present in primary cultures but not in situ, suggesting that the expression of these receptors might vary between different microglial activation states.


Assuntos
Quimiotaxia/efeitos dos fármacos , Microglia/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Fagocitose/efeitos dos fármacos , Receptores Purinérgicos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Cálcio/metabolismo , Células Cultivadas , Quimiotaxia/fisiologia , Feminino , Masculino , Camundongos , Microglia/metabolismo , Fagocitose/fisiologia , Transdução de Sinais/fisiologia
16.
Endocrinology ; 161(4)2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32005991

RESUMO

Evidence suggests that the hypothalamic-pituitary-gonadal (HPG) axis is active during the critical period for sexual differentiation of the ovine sexually dimorphic nucleus, which occurs between gestational day (GD) 60 and 90. Two possible neuropeptides that could activate the fetal HPG axis are kisspeptin and neurokinin B (NKB). We used GD85 fetal lambs to determine whether intravenous administration of kisspeptin-10 (KP-10) or senktide (NKB agonist) could elicit luteinizing hormone (LH) release. Immunohistochemistry and fluorescent in situ hybridization (FISH) were employed to localize these peptides in brains of GD60 and GD85 lamb fetuses. In anesthetized fetuses, KP-10 elicited robust release of LH that was accompanied by a delayed rise in serum testosterone in males. Pretreatment with the GnRH receptor antagonist (acyline) abolished the LH response to KP-10, confirming a hypothalamic site of action. In unanesthetized fetuses, senktide, as well as KP-10, elicited LH release. The senktide response of females was greater than that of males, indicating a difference in NKB sensitivity between sexes. Gonadotropin-releasing hormone also induced a greater LH discharge in females than in males, indicating that testosterone negative feedback is mediated through pituitary gonadotrophs. Kisspeptin and NKB immunoreactive cells in the arcuate nucleus were more abundant in females than in males. Greater than 85% of arcuate kisspeptin cells costained for NKB. FISH revealed that the majority of these were kisspeptin/NKB/dynorphin (KNDy) neurons. These results support the hypothesis that kisspeptin-GnRH signaling regulates the reproductive axis of the ovine fetus during the prenatal critical period acting to maintain a stable androgen milieu necessary for brain masculinization.


Assuntos
Hipotálamo/efeitos dos fármacos , Kisspeptinas/farmacologia , Hormônio Luteinizante/sangue , Testosterona/sangue , Animais , Feminino , Feto , Hormônio Liberador de Gonadotropina/farmacologia , Hipotálamo/metabolismo , Kisspeptinas/metabolismo , Masculino , Neurocinina B/metabolismo , Oligopeptídeos/farmacologia , Fragmentos de Peptídeos/farmacologia , Gravidez , Receptores de Kisspeptina-1/agonistas , Receptores da Neurocinina-3/agonistas , Ovinos , Substância P/análogos & derivados , Substância P/farmacologia
17.
Biochem Biophys Res Commun ; 524(3): 764-771, 2020 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-32037089

RESUMO

ß-Amyloid (Aß) plaque in the brains of patients with Alzheimer's disease (AD) is mainly caused by impaired clearance of Aß by glial cells, including microglia and astrocytes. Because microglia play an important protective role in the central nervous system, many efforts have been made to identify agents that effectively improve microglial Aß phagocytosis. This study found that TLQP-21, which is cleaved from VGF (VGF nerve growth factor inducible) precursor protein, enhanced Aß phagocytosis and degradation by microglial BV2 cells. TLQP-21 also improved microglial phagocytic activity and promoted fibrillar amyloid-ß (fAß) uptake by microglial BV2 cells via a C3AR1-dependent mechanism. Moreover, TLQP-21 stimulated Aß degradation by enhancing lysosome activity, thereby enhancing fAß clearance. These results suggest that treatment with TLQP-21 may be a novel therapeutic strategy to efficiently enhance microglial Aß clearance in AD.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Amiloide/metabolismo , Espaço Extracelular/metabolismo , Microglia/metabolismo , Fragmentos de Peptídeos/farmacologia , Amiloide/efeitos dos fármacos , Animais , Linhagem Celular , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Camundongos , Microglia/efeitos dos fármacos , Neuropeptídeos/farmacologia , Fagocitose/efeitos dos fármacos , Proteólise/efeitos dos fármacos , Receptores de Complemento/metabolismo
18.
Biochem Pharmacol ; 174: 113825, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31987854

RESUMO

We have previously reported that the spinal angiotensin (Ang) system is involved in the modulation of streptozotocin (STZ)-induced diabetic neuropathic pain in mice. An important drawback of this model however is the fact that the neuropathic pain is independent of hyperglycemia and produced by the direct stimulation of peripheral nerves. Here, using the leptin deficient ob/ob mouse as a type 2 diabetic model, we examined whether the spinal Ang system was involved in naturally occuring diabetic neuropathic pain. Blood glucose levels were increased in ob/ob mice at 5-15 weeks of age. Following the hyperglycemia, persistent tactile and thermal hyperalgesia were observed at 11-14 and 9-15 weeks of age, respectively, which was ameliorated by insulin treatment. At 12 weeks of age, the expression of Ang-converting enzyme (ACE) 2 in the spinal plasma membrane fraction was decreased in ob/ob mice. Spinal ACE2 was expressed in neurons and microglia but the number of NeuN-positive neurons was decreased in ob/ob mice. In addition, the intrathecal administration of Ang (1-7) and SB203580, a p38 MAPK inhibitor, attenuated hyperalgesia in ob/ob mice. The phosphorylation of spinal p38 MAPK was also attenuated by Ang (1-7) in ob/ob mice. These inhibitory effects of Ang (1-7) were prevented by A779, a Mas receptor antagonist. In conclusion, we revealed that the Ang (1-7)-generating system is downregulated in ob/ob mice and is accompanied by a loss of ACE2-positive neurons. Furthermore, Ang (1-7) decreased the diabetic neuropathic pain through inhibition of p38 MAPK phosphorylation via spinal Mas receptors.


Assuntos
Diabetes Mellitus Experimental/enzimologia , Diabetes Mellitus Tipo 2/enzimologia , Regulação para Baixo/fisiologia , Neuralgia/enzimologia , Peptidil Dipeptidase A/deficiência , Medula Espinal/enzimologia , Angiotensina I/metabolismo , Angiotensina I/farmacologia , Animais , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patologia , Regulação para Baixo/efeitos dos fármacos , Masculino , Camundongos , Camundongos Knockout , Camundongos Obesos , Camundongos Transgênicos , Neuralgia/genética , Neuralgia/patologia , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Peptidil Dipeptidase A/genética , Medula Espinal/efeitos dos fármacos , Medula Espinal/patologia , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
19.
Sci Rep ; 10(1): 1210, 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-31988368

RESUMO

Swine pneumonia is a great threat for pig industry around the world, which is usually accompanied with neutrophils infiltration in the airway. Although interleukin-8 (CXCL8) and its receptors, CXC chemokine receptor 1 and 2 (CXCR1/2) in human have been well documented, the expression and function of CXCR1/2 is still unknown in swine. To explore the feasibility to develop new veterinary anti-inflammatory drugs targeting porcine CXCR1/2, we detected CXCR1/2 expression in swine pneumonia through Real-Time PCR and immunohistochemistry for the first time. Two porcine CXCR1/2 antagonists, CXCL8(3-72)N11R/G31P (pN11R) and CXCL8(3-72)G31P (pG31P) were prepared and their anti-inflammatory effects were evaluated using cell chemotaxis assays and animal experiments. Our data showed that CXCR1/2 expression, which was closely related to neutrophil infiltration in the lung, was significantly up-regulated in swine pneumonia. The pN11R and pG31P could effectively inhibit the directional migration of neutrophils in vitro. In vivo data also indicated that both pN11R and pG31P significantly relieved LPS-induced pneumonia in mice through decreasing the expression of TNF-α, CXCL8, and IL-1ß, and inhibiting neutrophil influx into the lung. pG31P was more efficient. Our study suggested that it is possible to develop new veterinary anti-inflammatory drugs targeting porcine CXCR1/2, and pG31P is a promising candidate.


Assuntos
Interleucina-8/farmacologia , Interleucina-8/uso terapêutico , Fragmentos de Peptídeos/farmacologia , Fragmentos de Peptídeos/uso terapêutico , Pneumonia/tratamento farmacológico , Pneumonia/veterinária , Receptores de Interleucina-8A/antagonistas & inibidores , Receptores de Interleucina-8B/antagonistas & inibidores , Doenças dos Suínos/tratamento farmacológico , Animais , Movimento Celular/efeitos dos fármacos , Modelos Animais de Doenças , Descoberta de Drogas/métodos , Feminino , Imuno-Histoquímica , Interleucina-8/metabolismo , Lipopolissacarídeos/efeitos adversos , Lipopolissacarídeos/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Neutrófilos/metabolismo , Pneumonia/induzido quimicamente , Pneumonia/patologia , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Interleucina-8A/genética , Receptores de Interleucina-8A/imunologia , Receptores de Interleucina-8A/isolamento & purificação , Receptores de Interleucina-8B/genética , Receptores de Interleucina-8B/imunologia , Receptores de Interleucina-8B/isolamento & purificação , Transdução de Sinais/efeitos dos fármacos , Suínos
20.
Bratisl Lek Listy ; 121(1): 37-42, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31950838

RESUMO

OBJECTIVE: Hemopressin (Hp) is the first peptide ligand described for the CB1 cannabinoid receptor. Therefore, we aimed to investigate the effect of hemopressin on pencillin-induced epileptiform activity by using electrophysiological recording (ECoG) technique. METHODS: Male Wistar rats were anesthetized with urethane (1.25 g/kg), and epileptiform activity was induced by intracortical injection of penicillin (500 IU). Animals were randomly divided into eight groups. Subsequently, the rats were administered with saline or hemopressin as follows: saline control group (Group I: 2 µl/i.c.v/saline), hemopressin groups (Group II: 0.025 µg/i.c.v; Group III: 0.075 µg/i.c.v; Group IV: 0.15 µg/i.c.v; Group V: 0.3 µg/i.c.v; Group VI: 0.6 µg/i.c.v; Group VII: 1.2 µg/i.c.v; Group VIII: 2.4 µg/i.c.v). The various doses of hemopressin were injected intracerebroventricularly (i.c.v) 30 minutes after penicillin (2.5µl) injection. After hemopressin injection, ECoGs were recorded for three hours. RESULTS: Hp at doses of 0.075, 0.15, 0.3, 0.6, 1.2 and 2.4 µg/kg significantly increased the frequency of epileptiform ECoG activity compared to penicillin-injected group without changing the amplitude. The 0.6 µg hemopressin was the most effective dose to increase the epileptiform activity (p 0.05). CONCLUSIONS: The results of this study provided electrophysiological evidence for hemopressin to be modulating penicillin-induced epileptiform activity by acting as CB1 receptor antagonist. Further studies are required to elucidate the involved mechanism underlying this effect (Fig. 3, Ref. 40).


Assuntos
Epilepsia , Hemoglobinas , Penicilinas , Fragmentos de Peptídeos , Animais , Epilepsia/induzido quimicamente , Hemoglobinas/farmacologia , Masculino , Penicilinas/efeitos adversos , Fragmentos de Peptídeos/farmacologia , Distribuição Aleatória , Ratos , Ratos Wistar
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