Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 76
Filtrar
1.
Arterioscler Thromb Vasc Biol ; 43(7): 1234-1250, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37259865

RESUMO

BACKGROUND: TSP1 (thrombospondin-1)-a well-known angiogenesis inhibitor-mediates differential effects via interacting with cell surface receptors including CD36 (cluster of differentiation) and CD47. However, the role of TSP1 in regulating lymphangiogenesis is not clear. Our previous study suggested the importance of cell-specific CD47 blockade in limiting atherosclerosis. Further, our experiments revealed CD47 as a dominant TSP1 receptor in lymphatic endothelial cells (LECs). As the lymphatic vasculature is functionally linked to atherosclerosis, we aimed to investigate the effects of LEC TSP1-CD47 signaling inhibition on lymphangiogenesis and atherosclerosis. METHODS: Murine atherosclerotic and nonatherosclerotic arteries were utilized to investigate TSP1 expression using Western blotting and immunostaining. LEC-specific knockout mice were used to determine the in vivo role of LEC Cd47 in lymphangiogenesis and atherosclerosis. Various in vitro cell-based assays, in vivo Matrigel plug implantation, molecular biological techniques, and immunohistological approaches were used to evaluate the underlying signaling mechanisms. RESULTS: Elevated TSP1 expression was observed in mouse atherosclerotic aortic tissue compared with nonatherosclerotic control tissue. TSP1 at pathological concentrations suppressed both in vitro and in vivo lymphangiogenesis. Mechanistically, TSP1 inhibited VEGF (vascular endothelial growth factor)-C-induced AKT and eNOS activation in LEC and attenuated NO (nitric oxide) production. Further, CD47 silencing in LEC prevented the effects of TSP1 on lymphangiogenic AKT-eNOS signaling and lymphangiogenesis. Atheroprone AAV (adeno-associated virus) 8-PCSK9-injected LEC-specific Cd47 knockout mice (Cd47ΔLEC) had reduced atherosclerosis in both aorta and aortic root compared with control mice (Cd47ΔWT). However, no differences in metabolic parameters including body weight, plasma total cholesterol levels, and fasting blood glucose were observed. Additional immunostaining experiments performed on aortic root cross-sections indicated higher lymphatic vessel density in Cd47ΔLEC mice in comparison to controls. CONCLUSIONS: These findings demonstrate that TSP1 inhibits lymphangiogenesis via activation of CD47 in LEC, and loss of LEC Cd47 attenuates atherosclerotic lesion formation. Collectively, these results identify LEC CD47 as a potential therapeutic target in atherosclerosis.


Assuntos
Aterosclerose , Células Endoteliais , Animais , Camundongos , Aterosclerose/genética , Aterosclerose/prevenção & controle , Aterosclerose/metabolismo , Antígeno CD47/genética , Antígeno CD47/metabolismo , Células Endoteliais/metabolismo , Linfangiogênese , Camundongos Knockout , Pró-Proteína Convertase 9/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Trombospondina 1/genética , Trombospondina 1/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo
2.
Am J Physiol Renal Physiol ; 325(2): F248-F261, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37348027

RESUMO

Tubular epithelial cell fate following exposure to various types of injurious stimuli can be decided at distinct cell cycle checkpoints. One such checkpoint occurs during mitosis, known as the spindle assembly checkpoint, and is tightly regulated through the actions of cell division cycle protein 20 (CDC20). Due to our paucity of knowledge about the role of CDC20 in the kidney, the present study was designed to investigate the expression levels and distribution of CDC20 within the kidney and how pharmacological inhibition of CDC20 function affects kidney recovery using various rodent models of kidney injury. CDC20 is normally detected in distal tubules, but upon injury by either cisplatin administration or ureter obstruction, CDC20 accumulation is considerably elevated. Blockade of CDC20 activity using a selective pharmacological inhibitor, Apcin, lowered serum creatinine, tubular damage, and DNA injury following acute kidney injury compared with vehicle-treated mice. In unilateral ureteral obstruction, Apcin reduced tissue kidney injury molecule-1 levels, sirius red staining, and tubulointerstitial α-smooth muscle actin staining in the tissue. The findings in the present study demonstrated that elevations in CDC20 levels in the kidney are associated with kidney injury and that inhibition of CDC20 can alleviate and reverse some of the pathological effects on the architecture and function of kidney.NEW & NOTEWORTHY To our knowledge, this is the first study to characterize the expression and localization of cell division cycle 20 protein (CDC20) in normal and acute, and chronically injured kidneys. Tubular epithelial cell damage was markedly reduced through the administration of a selective inhibitor of CDC20, Apcin. This study provides new evidence that CDC20 can be induced in damaged kidney cells and negatively impact the recovery of the kidney following acute kidney injury.


Assuntos
Injúria Renal Aguda , Obstrução Ureteral , Camundongos , Animais , Proteínas de Ciclo Celular/metabolismo , Rim/metabolismo , Carbamatos/farmacologia , Obstrução Ureteral/complicações , Injúria Renal Aguda/complicações
3.
J Neurophysiol ; 126(1): 123-139, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34077281

RESUMO

Primitive-based models of motor learning suggest that adaptation occurs by tuning the responses of motor primitives. Based on this idea, we consider motor learning as an information encoding procedure, that is, a procedure of encoding a motor skill into primitives. The capacity of encoding is determined by the number of recruited primitives, which depends on how many primitives are "visited" by the movement, and this leads to a rather counterintuitive prediction that faster movement, where a larger number of motor primitives are involved, allows learning more complicated motor skills. Here, we provide a set of experimental results that support this hypothesis. First, we show that learning occurs only with movement, that is, only with nonzero encoding capacity. When participants were asked to counteract a rotating force applied to a robotic handle, they were unable to do so when maintaining a static posture but were able to adapt when making small circular movements. Our second experiment further investigated how adaptation is affected by movement speed. When adapting to a simple (low-information-content) force field, fast (high-capacity) movement did not have an advantage over slow (low-capacity) movement. However, for a complex (high-information-content) force field, the fast movement showed a significant advantage over slow movement. Our final experiment confirmed that the observed benefit of high-speed movement is only weakly affected by mechanical factors. Taken together, our results suggest that the encoding capacity is a genuine limiting factor of human motor adaptation.NEW & NOTEWORTHY We propose a novel concept called "encoding capacity" of motor adaptation, which describes an inherent limiting-factor of our brain's ability to learn new motor skills, just like any other storage system. By reinterpreting the existing primitive-based models of motor learning, we hypothesize that the encoding capacity is determined by the size of the movement, and present a set of experimental evidence suggesting that such limiting effect of encoding capacity does exist in human motor adaptation.


Assuntos
Adaptação Fisiológica/fisiologia , Destreza Motora/fisiologia , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Eletromiografia/métodos , Feminino , Humanos , Masculino , Adulto Jovem
4.
Physiol Genomics ; 51(9): 449-461, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31398086

RESUMO

A resurgence in the development of newer gene therapy systems has led to recent successes in the treatment of B cell cancers, retinal degeneration and neuromuscular atrophy. Gene therapy offers the ability to treat the patient at the root cause of their malady by restoring normal gene function and arresting the pathological progression of their genetic disease. The current standard of care for most genetic diseases is based upon the symptomatic treatment with polypharmacy while minimizing any potential adverse effects attributed to the off-target and drug-drug interactions on the target or other organs. In the kidney, however, the development of gene therapy modifications to specific renal cells has lagged far behind those in other organ systems. Some positive strides in the past few years provide continued enthusiasm to invest the time and effort in the development of new gene therapy vectors for medical intervention to treat kidney diseases. This mini-review will systematically describe the pros and cons of the most commonly tested gene therapy vector systems derived from adenovirus, retrovirus, and adeno-associated virus and provide insight about their potential utility as a therapy for various types of genetic diseases in the kidney.


Assuntos
Terapia Genética/métodos , Nefropatias/terapia , Adenoviridae/genética , Animais , Proteínas do Capsídeo/genética , Dependovirus/genética , Vetores Genéticos/administração & dosagem , Humanos , Lentivirus/genética , Camundongos , Transdução Genética/métodos
5.
Biochem Biophys Res Commun ; 515(1): 72-76, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31128920

RESUMO

Ischemic injury is a primary contributor to the initiation of renal tubular epithelial cell damage in sickle cell disease (SCD). In this study, we investigated the effects of bilateral ischemia-reperfusion injury, which is a common type of acute kidney injury (AKI), in male and female genetic mouse model of SCD. Bilateral occlusion of both renal hila for 21 min led to a significantly higher detection of established serum markers of AKI (creatinine, KIM-1 and NGAL) compared to sham-operated male SCD mice. Severe damage to the outer medullary tubules was determined in the ischemia-reperfision injury (IRI)-treated SCD male mice. In female SCD mice with a longer ischemic time (23 min), the serum markers of AKI were not as highly elevated compared to their male counterparts, and the extent of outer medullary tubular injury was less severe. To assess the potential benefit in the use of hydroxyurea (50 mg/kg IP) following bilateral renal IRI, we observed that the serum markers of AKI and the outer medullary tubular damage were markedly improved compared to male SCD mice that were not treated with hydroxyurea. In this study, we confirmed that male SCD mice were more susceptible to increased tubular damage and a loss in renal function compared to female SCD mice, and that hydroxyurea may partially prevent the extent of tubular injury following severe ischemia-reperfusion injury in SCD.


Assuntos
Injúria Renal Aguda/fisiopatologia , Anemia Falciforme/tratamento farmacológico , Hidroxiureia/farmacologia , Túbulos Renais/efeitos dos fármacos , Traumatismo por Reperfusão/fisiopatologia , Injúria Renal Aguda/sangue , Anemia Falciforme/sangue , Animais , Antidrepanocíticos/farmacologia , Biomarcadores/sangue , Creatinina/sangue , Modelos Animais de Doenças , Feminino , Receptor Celular 1 do Vírus da Hepatite A/sangue , Túbulos Renais/metabolismo , Túbulos Renais/patologia , Lipocalina-2/sangue , Masculino , Camundongos , Traumatismo por Reperfusão/sangue
6.
J Pharmacol Exp Ther ; 364(2): 287-299, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29187590

RESUMO

Ischemia-reperfusion injury (IRI) is a common cause of acute kidney injury (AKI), which is an increasing problem in the clinic and has been associated with elevated rates of mortality. Therapies to treat AKI are currently not available, so identification of new targets that can be modulated to ameliorate renal damage upon diagnosis of AKI is essential. In this study, a novel cannabinoid receptor 2 (CB2) agonist, SMM-295 [3'-methyl-4-(2-(thiophen-2-yl)propan-2-yl)biphenyl-2,6-diol], was designed, synthesized, and tested in vitro and in silico. Molecular docking of SMM-295 into a CB2 active-state homology model showed that SMM-295 interacts well with key amino acids to stabilize the active state. In human embryonic kidney 293 cells, SMM-295 was capable of reducing cAMP production with 66-fold selectivity for CB2 versus cannabinoid receptor 1 and dose-dependently increased mitogen-activated protein kinase and Akt phosphorylation. In vivo testing of the CB2 agonist was performed using a mouse model of bilateral IRI, which is a common model to mimic human AKI, where SMM-295 was immediately administered upon reperfusion of the kidneys after the ischemia episode. Histologic damage assessment 48 hours after reperfusion demonstrated reduced tubular damage in the presence of SMM-295. This was consistent with reduced plasma markers of renal dysfunction (i.e., creatinine and neutrophil gelatinase-associated lipocalin) in SMM-295-treated mice. Mechanistically, kidneys treated with SMM-295 were shown to have elevated activation of Akt with reduced terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine nick-end labeling (TUNEL)-positive cells compared with vehicle-treated kidneys after IRI. These data suggest that selective CB2 receptor activation could be a potential therapeutic target in the treatment of AKI.


Assuntos
Compostos de Bifenilo/farmacologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Túbulos Renais/efeitos dos fármacos , Túbulos Renais/patologia , Receptor CB2 de Canabinoide/agonistas , Traumatismo por Reperfusão/patologia , Tiofenos/farmacologia , Animais , Compostos de Bifenilo/química , Compostos de Bifenilo/metabolismo , Compostos de Bifenilo/uso terapêutico , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Simulação de Acoplamento Molecular , Permeabilidade , Conformação Proteica , Receptor CB2 de Canabinoide/química , Receptor CB2 de Canabinoide/metabolismo , Traumatismo por Reperfusão/tratamento farmacológico , Solubilidade , Tiofenos/química , Tiofenos/metabolismo , Tiofenos/uso terapêutico
7.
Neural Comput ; 30(7): 1930-1960, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29902113

RESUMO

Nearest-neighbor estimators for the Kullback-Leiber (KL) divergence that are asymptotically unbiased have recently been proposed and demonstrated in a number of applications. However, with a small number of samples, nonparametric methods typically suffer from large estimation bias due to the nonlocality of information derived from nearest-neighbor statistics. In this letter, we show that this estimation bias can be mitigated by modifying the metric function, and we propose a novel method for learning a locally optimal Mahalanobis distance function from parametric generative models of the underlying density distributions. Using both simulations and experiments on a variety of data sets, we demonstrate that this interplay between approximate generative models and nonparametric techniques can significantly improve the accuracy of nearest-neighbor-based estimation of the KL divergence.

8.
Bioorg Med Chem ; 26(17): 4787-4796, 2018 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-30145051

RESUMO

Pleuromutilin is a promising pharmacophore to design new antibacterial agents for Gram-positive bacteria. However, there are limited studies on the development of pleuromutilin analogues that inhibit growth of Mycobacterium tuberculosis (Mtb). In screening of our library of pleuromutilin derivatives, UT-800 (1) was identified to kill replicating- and non-replicating Mtb with the MIC values of 0.83 and 1.20 µg/mL, respectively. UT-800 also kills intracellular Mtb faster than rifampicin at 2× MIC concentrations. Pharmacokinetic studies indicate that 1 has an oral bioavailability with an average F-value of 27.6%. Pleuromutilin may have the potential to be developed into an orally administered anti-TB drug.


Assuntos
Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Administração Oral , Animais , Antituberculosos/administração & dosagem , Antituberculosos/farmacocinética , Área Sob a Curva , Disponibilidade Biológica , Células CACO-2 , Diterpenos/administração & dosagem , Diterpenos/química , Diterpenos/farmacocinética , Diterpenos/farmacologia , Feminino , Meia-Vida , Humanos , Concentração Inibidora 50 , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/crescimento & desenvolvimento , Compostos Policíclicos , Pleuromutilinas
9.
Mol Pharmacol ; 91(1): 1-13, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27913654

RESUMO

Targeting vascular endothelial growth factor (VEGF) is a common treatment strategy for neovascular eye disease, a major cause of vision loss in diabetic retinopathy and age-related macular degeneration. However, the decline in clinical efficacy over time in many patients suggests that monotherapy of anti-VEGF protein therapeutics may benefit from adjunctive treatments. Our previous work has shown that through decreased activation of the cytoskeletal protein paxillin, growth factor-induced ischemic retinopathy in the murine oxygen-induced retinopathy model could be inhibited. In this study, we demonstrated that VEGF-dependent activation of the Src/FAK/paxillin signalsome is required for human retinal endothelial cell migration and proliferation. Specifically, the disruption of focal adhesion kinase (FAK) and paxillin interactions using the small molecule JP-153 inhibited Src-dependent phosphorylation of paxillin (Y118) and downstream activation of Akt (S473), resulting in reduced migration and proliferation of retinal endothelial cells stimulated with VEGF. However, this effect did not prevent the initial activation of either Src or FAK. Furthermore, topical application of a JP-153-loaded microemulsion affected the hallmark features of pathologic retinal angiogenesis, reducing neovascular tuft formation and increased avascular area, in a dose-dependent manner. In conclusion, our results suggest that using small molecules to modulate the focal adhesion protein paxillin is an effective strategy for treating pathologic retinal neovascularization. To our knowledge, this is the first paradigm validating modulation of paxillin to inhibit angiogenesis. As such, we have identified and developed a novel class of small molecules aimed at targeting focal adhesion protein interactions that are essential for pathologic neovascularization in the eye.


Assuntos
Benzoxazinas/farmacologia , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Paxilina/metabolismo , Neovascularização Retiniana/metabolismo , Transdução de Sinais/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/farmacologia , Fator A de Crescimento do Endotélio Vascular/farmacologia , Quinases da Família src/metabolismo , Animais , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Humanos , Camundongos Endogâmicos C57BL , Modelos Biológicos , Oxigênio , Neovascularização Retiniana/patologia
10.
Physiol Genomics ; 54(8): 316-318, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35816650
11.
Physiol Genomics ; 49(11): 659-666, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28939644

RESUMO

Lysophosphatidic acid (LPA) is a bioactive phospholipid that can exert diverse biological effects in various diseased states of the kidney by activating at least six cognate G protein-coupled receptors and its complex network of heterotrimeric G proteins. In many models of acute and chronic kidney injury, pathological elevations in LPA promotes abnormal changes in renal tubular epithelial cell architecture by activating apoptotic signaling, recruits immune cells to the site of injury, and stimulates profibrotic signaling by increasing gene transcription. In renal cancers, LPA can promote vascular cell proliferation and tumor cell invasion. In this review, a summary will be provided to describe the involvement of LPA, its synthetic enzymes, and its associated receptors in normal and diseased kidneys. Further elucidation of the LPA system may open new doors in developing a lipid-receptor therapeutic platform for kidney diseases.


Assuntos
Rim/metabolismo , Lisofosfolipídeos/metabolismo , Receptores de Ácidos Lisofosfatídicos/metabolismo , Animais , Biocatálise , Humanos , Rim/patologia , Nefropatias/metabolismo , Lisofosfolipídeos/biossíntese , Receptores de Ácidos Lisofosfatídicos/genética , Transdução de Sinais
12.
Am J Physiol Renal Physiol ; 312(4): F551-F555, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-27927651

RESUMO

Ischemia-reperfusion injury (IRI) is a common cause of acute kidney injury leading to an induction of oxidative stress, cellular dysfunction, and loss of renal function. DNA damage, including oxidative base modifications and physical DNA strand breaks, is a consequence of renal IRI. Like many other organs in the body, a redundant and highly conserved set of endogenous repair pathways have evolved to selectively recognize the various types of cellular DNA damage and combat its negative effects on cell viability. Severe damage to the DNA, however, can trigger cell death and elimination of the injured tubular epithelial cells. In this minireview, we summarize the state of the current field of DNA damage and repair in the kidney and provide some expected and, in some cases, unexpected effects of IRI on DNA damage and repair in the kidney. These findings may be applicable to other forms of acute kidney injury and could provide new opportunities for renal research.


Assuntos
Injúria Renal Aguda/genética , Dano ao DNA , Reparo do DNA , Túbulos Renais/metabolismo , Traumatismo por Reperfusão/genética , Injúria Renal Aguda/metabolismo , Injúria Renal Aguda/patologia , Animais , Morte Celular , Proliferação de Células , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Humanos , Túbulos Renais/patologia , Estresse Oxidativo , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Transdução de Sinais
13.
Am J Physiol Renal Physiol ; 313(5): F1124-F1132, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28747360

RESUMO

Consumption of cannabis and various related products (cannabinoids) for both medicinal and recreational use is gaining popularity. Furthermore, regulatory changes are fostering a cultural shift toward increasing liberalization of cannabis use, thereby increasing the likelihood of even larger numbers of individuals being exposed in the future. The two different types of receptors (CB1 and CB2) that are activated by the pharmacologically active ingredients of cannabis are found in numerous tissues, including the kidneys. Experimental studies suggest that stimulation of these receptors using pharmacologic agents or their naturally occurring ligands could have both deleterious and beneficial effects on the kidneys, depending on receptor distribution, type of renal insult, or the timing of the activation during acute or chronic states of kidney injury. To date, the mechanisms by which the CB1 or CB2 receptors are involved in the pathology of these renal conditions remain to be fully described. Furthermore, a better understanding of the impact of exocannabinoids and endocannabinoids on the renal system may lead to the development of new drugs to treat kidney disease and its complications. Given the increasing public health relevance of cannabis exposure, it is clear that more research is necessary to clarify the various physiological and pathophysiological effects of cannabis and related analogs on the kidney. This will help limit the deleterious effects of these substances while promoting their potential beneficial impact on renal function in various types of kidney diseases.


Assuntos
Canabinoides/farmacologia , Endocanabinoides/farmacologia , Nefropatias/tratamento farmacológico , Rim/efeitos dos fármacos , Animais , Humanos , Rim/metabolismo , Nefropatias/metabolismo , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/metabolismo
14.
IEEE Trans Robot ; 33(1): 22-37, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28966566

RESUMO

Robotic instruments based on concentric tube technology are well suited to minimally invasive surgery since they are slender, can navigate inside small cavities and can reach around sensitive tissues by taking on shapes of varying curvature. Elastic instabilities can arise, however, when rotating one precurved tube inside another. In contrast to prior work that considered only tubes of piecewise constant precurvature, we allow precurvature to vary along the tube's arc length. Stability conditions for a planar tube pair are derived and used to formulate an optimal design problem. An analytic formulation of the optimal precurvature function is derived that achieves a desired tip orientation range while maximizing stability and respecting bending strain limits. This formulation also includes straight transmission segments at the proximal ends of the tubes. The result, confirmed by both numerical and physical experiment, enables designs with enhanced stability in comparison to designs of constant precurvature.

15.
Physiol Genomics ; 48(7): 429-45, 2016 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-27199453

RESUMO

Autosomal dominant polycystic kidney disease (ADPKD) is a signalopathy of renal tubular epithelial cells caused by naturally occurring mutations in two distinct genes, polycystic kidney disease 1 (PKD1) and 2 (PKD2). Genetic variants in PKD1, which encodes the polycystin-1 (PC-1) protein, remain the predominant factor associated with the pathogenesis of nearly two-thirds of all patients diagnosed with PKD. Although the relationship between defective PC-1 with renal cystic disease initiation and progression remains to be fully elucidated, there are numerous clinical studies that have focused upon the control of effector systems involving heterotrimeric G protein regulation. A major regulator in the activation state of heterotrimeric G proteins are G protein-coupled receptors (GPCRs), which are defined by their seven transmembrane-spanning regions. PC-1 has been considered to function as an unconventional GPCR, but the mechanisms by which PC-1 controls signal processing, magnitude, or trafficking through heterotrimeric G proteins remains to be fully known. The diversity of heterotrimeric G protein signaling in PKD is further complicated by the presence of non-GPCR proteins in the membrane or cytoplasm that also modulate the functional state of heterotrimeric G proteins within the cell. Moreover, PC-1 abnormalities promote changes in hormonal systems that ultimately interact with distinct GPCRs in the kidney to potentially amplify or antagonize signaling output from PC-1. This review will focus upon the canonical and noncanonical signaling pathways that have been described in PKD with specific emphasis on which heterotrimeric G proteins are involved in the pathological reorganization of the tubular epithelial cell architecture to exacerbate renal cystogenic pathways.


Assuntos
Proteínas Heterotriméricas de Ligação ao GTP/genética , Doenças Renais Policísticas/genética , Rim Policístico Autossômico Dominante/genética , Transdução de Sinais/genética , Animais , Humanos , Mutação/genética , Canais de Cátion TRPP/genética
16.
J Pharmacol Exp Ther ; 353(2): 235-45, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25628392

RESUMO

Heterotrimeric G proteins play a crucial role in regulating signal processing to maintain normal cellular homeostasis, and subtle perturbations in its activity can potentially lead to the pathogenesis of renal disorders or diseases. Cell-surface receptors and accessory proteins, which normally modify and organize the coupling of individual G protein subunits, contribute to the regulation of heterotrimeric G protein activity and their convergence and/or divergence of downstream signaling initiated by effector systems. Activators of G protein signaling (AGS) are a family of accessory proteins that intervene at multiple distinct points during the activation-inactivation cycle of G proteins, even in the absence of receptor stimulation. Perturbations in the expression of individual AGS proteins have been reported to modulate signal transduction pathways in a wide array of diseases and disorders within the brain, heart, immune system, and more recently, the kidney. This review will provide an overview of the expression profile, localization, and putative biologic role of the AGS family in the context of normal and diseased states of the kidney.


Assuntos
Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Rim/metabolismo , Transdução de Sinais , Animais , Humanos , Subunidades Proteicas/metabolismo , Transporte Proteico
17.
Proc Natl Acad Sci U S A ; 109(52): 21462-7, 2012 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-23236168

RESUMO

Polycystic kidney diseases are the most common genetic diseases that affect the kidney. There remains a paucity of information regarding mechanisms by which G proteins are regulated in the context of polycystic kidney disease to promote abnormal epithelial cell expansion and cystogenesis. In this study, we describe a functional role for the accessory protein, G-protein signaling modulator 1 (GPSM1), also known as activator of G-protein signaling 3, to act as a modulator of cyst progression in an orthologous mouse model of autosomal dominant polycystic kidney disease (ADPKD). A complete loss of Gpsm1 in the Pkd1(V/V) mouse model of ADPKD, which displays a hypomorphic phenotype of polycystin-1, demonstrated increased cyst progression and reduced renal function compared with age-matched cystic Gpsm1(+/+) and Gpsm1(+/-) mice. Electrophysiological studies identified a role by which GPSM1 increased heteromeric polycystin-1/polycystin-2 ion channel activity via Gßγ subunits. In summary, the present study demonstrates an important role for GPSM1 in controlling the dynamics of cyst progression in an orthologous mouse model of ADPKD and presents a therapeutic target for drug development in the treatment of this costly disease.


Assuntos
Proteínas de Transporte/metabolismo , Progressão da Doença , Rim Policístico Autossômico Dominante/metabolismo , Rim Policístico Autossômico Dominante/patologia , Animais , Modelos Animais de Doenças , Fenômenos Eletrofisiológicos , Imunofluorescência , Genótipo , Inibidores de Dissociação do Nucleotídeo Guanina , Rim/metabolismo , Rim/patologia , Rim/fisiopatologia , Testes de Função Renal , Camundongos , Rim Policístico Autossômico Dominante/fisiopatologia , Transporte Proteico , Canais de Cátion TRPP/metabolismo
18.
Mol Pharmacol ; 86(4): 369-77, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25028481

RESUMO

Heterotrimeric G-proteins play a crucial role in the control of renal epithelial cell function during homeostasis and in response to injury. In this report, G-protein ßγ subunit (Gßγ) dimer activity was evaluated during the process of tubular repair after renal ischemia-reperfusion injury (IRI) in male Sprague Dawley rats. Rats were treated with a small molecule inhibitor of Gßγ activity, gallein (30 or 100 mg/kg), 1 hour after reperfusion and every 24 hours for 3 additional days. After IRI, renal dysfunction was prolonged after the high-dose gallein treatment in comparison with vehicle treatment during the 7-day recovery period. Renal tubular repair in the outer medulla 7 days after IRI was significantly (P < 0.001) attenuated after treatment with high-dose gallein (100 mg/kg) in comparison with low-dose gallein (30 mg/kg), or the vehicle and fluorescein control groups. Gallein treatment significantly reduced (P < 0.05) the number of proliferating cell nuclear antigen-positive tubular epithelial cells at 24 hours after the ischemia-reperfusion phase in vivo. In vitro application of gallein on normal rat kidney (NRK-52E) proximal tubule cells significantly reduced (P < 0.05) S-phase cell cycle entry compared with vehicle-treated cells as determined by 5'-bromo-2'-deoxyuridine incorporation. Taken together, these data suggest that Gßγ signaling contributes to the maintenance and repair of renal tubular epithelium and may be a novel therapeutic target for the development of drugs to treat acute kidney injury.


Assuntos
Síndrome Cardiorrenal/tratamento farmacológico , Subunidades beta da Proteína de Ligação ao GTP/metabolismo , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Rim/efeitos dos fármacos , Traumatismo por Reperfusão/metabolismo , Animais , Síndrome Cardiorrenal/metabolismo , Linhagem Celular , Movimento Celular , Proliferação de Células , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/fisiologia , Subunidades beta da Proteína de Ligação ao GTP/antagonistas & inibidores , Subunidades gama da Proteína de Ligação ao GTP/antagonistas & inibidores , Rim/metabolismo , Rim/patologia , Masculino , Multimerização Proteica , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/tratamento farmacológico , Xantenos/farmacologia , Xantenos/uso terapêutico
19.
J Biol Chem ; 288(22): 15843-53, 2013 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-23609438

RESUMO

The intermediate conductance calcium-activated potassium channel KCa3.1 contributes to a variety of cell activation processes in pathologies such as inflammation, carcinogenesis, and vascular remodeling. We examined the electrophysiological and transcriptional mechanisms by which KCa3.1 regulates vascular smooth muscle cell (VSMC) proliferation. Platelet-derived growth factor-BB (PDGF)-induced proliferation of human coronary artery VSMCs was attenuated by lowering intracellular Ca(2+) concentration ([Ca(2+)]i) and was enhanced by elevating [Ca(2+)]i. KCa3.1 blockade or knockdown inhibited proliferation by suppressing the rise in [Ca(2+)]i and attenuating the expression of phosphorylated cAMP-response element-binding protein (CREB), c-Fos, and neuron-derived orphan receptor-1 (NOR-1). This antiproliferative effect was abolished by elevating [Ca(2+)]i. KCa3.1 overexpression induced VSMC proliferation, and potentiated PDGF-induced proliferation, by inducing CREB phosphorylation, c-Fos, and NOR-1. Pharmacological stimulation of KCa3.1 unexpectedly suppressed proliferation by abolishing the expression and activity of KCa3.1 and PDGF ß-receptors and inhibiting the rise in [Ca(2+)]i. The stimulation also attenuated the levels of phosphorylated CREB, c-Fos, and cyclin expression. After KCa3.1 blockade, the characteristic round shape of VSMCs expressing high l-caldesmon and low calponin-1 (dedifferentiation state) was maintained, whereas KCa3.1 stimulation induced a spindle-shaped cellular appearance, with low l-caldesmon and high calponin-1. In conclusion, KCa3.1 plays an important role in VSMC proliferation via controlling Ca(2+)-dependent signaling pathways, and its modulation may therefore constitute a new therapeutic target for cell proliferative diseases such as atherosclerosis.


Assuntos
Sinalização do Cálcio/fisiologia , Proliferação de Células , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Indutores da Angiogênese/farmacologia , Aterosclerose/tratamento farmacológico , Aterosclerose/genética , Aterosclerose/metabolismo , Becaplermina , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação a Calmodulina/genética , Proteínas de Ligação a Calmodulina/metabolismo , Células Cultivadas , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/antagonistas & inibidores , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Músculo Liso Vascular/citologia , Miócitos de Músculo Liso/citologia , Fosforilação/fisiologia , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-fos/metabolismo , Proteínas Proto-Oncogênicas c-sis/farmacologia , Calponinas
20.
Life Sci ; 336: 122317, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38040245

RESUMO

Interstitial cystitis (IC), also called painful bladder syndrome (PBS), is 2 to 5 times more common in women than in men, yet its cause and pathogenesis remain unclear. In our study using the cyclophosphamide (CYP)-induced mouse model of cystitis, histological evaluation of the urinary bladder (UB) lamina propria (LP) showed immune cell infiltrations, indicating moderate to severe inflammation. In this study, we noticed a differential expression of a subset of microRNAs (miRs) in the UB cells (UBs) of CYP-induced cystitis as compared to the control. UB inflammatory scores and inflammatory signaling were also elevated in CYP-induced cystitis as compared to control. We identified eight UBs miRs that exhibited altered expression after CYP induction and are predicted to have a role in inflammation and smooth muscle function (miRs-34c-5p, -34b-3p, -212-3p, -449a-5p, -21a-3p, -376b-3p, -376b-5p and - 409-5p). Further analysis using ELISA for inflammatory markers and real-time PCR (RT-PCR) for differentially enriched miRs identified miR-34c as a potential target for the suppression of UB inflammation in cystitis. Blocking miR-34c by antagomir ex vivo reduced STAT3, TGF-ß1, and VEGF expression in the UBs, which was induced during cystitis as compared to control. Interestingly, miR-34c inhibition also downregulated ROCK2 but elevated ROCK1 expression in bladder and detrusor cells. Thus, the present study shows that targeting miR-34c can mitigate the STAT3, TGF-ß, and VEGF, inflammatory signaling in UB, and suppress ROCK2 expression in UBs to effectively suppress the inflammatory response in cystitis. This study highlights miR-34c as a potential biomarker and/or serves as the basis for new therapies for the treatment of cystitis.


Assuntos
Cistite Intersticial , Cistite , MicroRNAs , Masculino , Camundongos , Animais , Humanos , Feminino , Fator A de Crescimento do Endotélio Vascular/metabolismo , Cistite/induzido quimicamente , Bexiga Urinária/metabolismo , Cistite Intersticial/genética , Cistite Intersticial/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Ciclofosfamida/efeitos adversos , Inflamação/metabolismo , Quinases Associadas a rho/genética , Quinases Associadas a rho/metabolismo
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa