RESUMO
Chronic kidney disease (CKD) is linked to greater prevalence and rapid progression of calcific aortic valve disease (CAVD) characterized by valvular leaflet fibrosis and calcification. Fibroblast growth factor 23 (FGF23) level is elevated, and anti-aging protein Klotho is reduced in CKD patients. However, the roles of FGF23 and Klotho in the mechanism of aortic valve fibrosis and calcification remain unclear. We hypothesized that FGF23 mediates CKD-induced CAVD by enhancing aortic valve interstitial cell (AVIC) fibrosis and calcification, while soluble Klotho inhibits FGF23 effect. Methods and Results: In an old mouse model of CKD, kidney damages were accompanied by aortic valve thickening and calcification. FGF23 levels in plasma and aortic valve were increased, while Klotho levels were decreased. Recombinant FGF23 elevated the inflammatory, fibrogenic, and osteogenic activities in AVICs. Neutralizing antibody or shRNA targeting FGF23 suppressed the pathobiological activities in AVICs from valves affected by CAVD. FGF23 exerts its effects on AVICs via FGF receptor (FGFR)/Yes-associated protein (YAP) signaling, and inhibition of FGFR/YAP reduced FGF23's potency in AVICs. Recombinant Klotho downregulated the pathobiological activities in AVICs exposed to FGF23. Incubation of FGF23 with Klotho formed complexes and decreased FGF23's potency. Further, treatment of CKD mice with recombinant Klotho attenuated aortic valve lesions. Conclusion: This study demonstrates that CKD induces FGF23 accumulation, Klotho insufficiency and aortic valve lesions in old mice. FGF23 upregulates the inflammatory, fibrogenic and osteogenic activities in AVICs via the FGFR/YAP signaling pathway. Soluble Klotho suppresses FGF23 effect through molecular interaction and is capable of mitigating CKD-induced CAVD.
Assuntos
Valva Aórtica , Fator de Crescimento de Fibroblastos 23 , Fatores de Crescimento de Fibroblastos , Glucuronidase , Proteínas Klotho , Insuficiência Renal Crônica , Proteínas Klotho/metabolismo , Fator de Crescimento de Fibroblastos 23/metabolismo , Animais , Insuficiência Renal Crônica/metabolismo , Glucuronidase/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Camundongos , Valva Aórtica/metabolismo , Valva Aórtica/patologia , Calcinose/metabolismo , Masculino , Transdução de Sinais , Camundongos Endogâmicos C57BL , Humanos , Estenose da Valva Aórtica/metabolismo , Modelos Animais de DoençasRESUMO
Introduction: Sepsis is prevalent in the elderly population with increased incidence and mortality. Currently, the mechanism by which aging increases the susceptibility to sepsis and worsens outcome is unclear. We tested the hypothesis that aging exacerbates cardiac dysfunction in sepsis through a Toll-like receptor 2 (TLR2)-dependent mechanism. Methods: Male young adult (4-6 months) and old (18-20 months) wild type (WT) and TLR2 knockout (KO) mice were subject to moderate sepsis by cecal ligation and puncture. Additional groups of young adult and old WT mice were treated with TLR2 agonist Pam3CSK4. Left ventricle (LV) performance was evaluated with a pressure-volume microcatheter. Tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-6 and monocyte chemoattractant protein-1 (MCP-1) in the myocardium and plasma were assessed using enzyme-linked immunosorbent assay. Results: Sepsis reduced LV ejection fraction and cardiac output in both young adult and old WT mice. However, identical CLP caused more severe cardiac dysfunction and high mortality in old WT mice that were accompanied by greater levels of TNF-α, IL-1ß, IL-6 and MCP-1 in the myocardium and plasma. TLR2 KO diminished aging-related difference in myocardial and systemic inflammatory response, resulting in improved cardiac function and decreased mortality in old septic mice. In addition, higher myocardial TLR2 levels in old WT mice resulted in greater myocardial inflammatory response and worse cardiac dysfunction following administration of TLR2 agonist. Conclusion: Moderate sepsis results in greater cardiac dysfunction and significant mortality in old mice. Aging elevates TLR2 level/activity to exacerbate the inflammatory response to sepsis, leading to worse cardiac dysfunction and mortality.
RESUMO
Calcific aortic valve disease (CAVD) is common in people over the age of 65. Progressive valvular calcification is a characteristic of CAVD and due to chronic inflammation in aortic valve interstitial cells (AVICs) resulting in CAVD progression. IL-38 is a naturally occurring anti-inflammatory cytokine; here, we report lower levels of endogenous IL-38 in AVICs isolated from patients' CAVD valves compared to AVICs from non-CAVD valves. Recombinant IL-38 suppressed spontaneous inflammatory activity and calcium deposition in cultured AVICs. In mice, knockdown of IL-38 enhanced the production of inflammatory mediators in murine AVICs exposed to the proinflammatory stimulant matrilin-2. We also observed that in cultured AVICs matrilin-2 stimulation activated the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome with procaspase-1 cleavage into active caspase-1. The addition of IL-38 to matrilin-2-treated AVICs suppressed caspase-1 activation and reduced the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, runt-related transcription factor 2, and alkaline phosphatase. Aged IL-38-deficient mice fed a high-fat diet exhibited aortic valve lesions compared to aged wild-type mice fed the same diet. The interleukin-1 receptor 9 (IL-1R9) is the putative receptor mediating the anti-inflammatory properties of IL-38; we observed that IL-1R9-deficient mice exhibited spontaneous aortic valve thickening and greater calcium deposition in AVICs compared to wild-type mice. These data demonstrate that IL-38 suppresses spontaneous and stimulated osteogenic activity in aortic valve via inhibition of the NLRP3 inflammasome and caspase-1. The findings of this study suggest that IL-38 has therapeutic potential for prevention of CAVD progression.
Assuntos
Estenose da Valva Aórtica , Calcinose , Interleucinas , Animais , Anti-Inflamatórios/farmacologia , Valva Aórtica/metabolismo , Valva Aórtica/patologia , Estenose da Valva Aórtica/tratamento farmacológico , Estenose da Valva Aórtica/genética , Estenose da Valva Aórtica/metabolismo , Calcinose/tratamento farmacológico , Cálcio/metabolismo , Caspases/metabolismo , Células Cultivadas , Humanos , Inflamassomos/metabolismo , Interleucina-1 , Interleucinas/genética , Interleucinas/metabolismo , Interleucinas/farmacologia , Proteínas Matrilinas/farmacologia , Camundongos , Camundongos Endogâmicos NOD , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Osteogênese , Receptores de Interleucina-9/genética , Proteínas Recombinantes/farmacologiaRESUMO
This study tested the hypothesis that Toll-like receptor 2 (TLR2) augments the inflammatory responses and adverse remodeling in aging hearts to exacerbate myocardial injury and cardiac dysfunction. Methods: Old (20-22 months old) and adult (4-6 months old) mice of C57BL/6 wild-type and TLR2 knockout (KO) were subjected to coronary artery ligation (30 minutes) and reperfusion (3 or 14 days). Left ventricle function was assessed using a pressure-volume microcatheter. Cardiac infarct size was determined by histology. Levels of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), matrix metalloproteinase 9 (MMP 9), and collagen I in non-ischemic myocardium were assessed by immunoblotting. Monocyte chemoattractant protein-1 (MCP-1), keratinocyte chemoattractant (KC), and interleukin-6 (IL-6) levels in ischemic and non-ischemic myocardium were measured by enzyme-linked immunosorbent assay (ELISA). TLR2 expression in the myocardium of untreated wild type mice was also measured by immunoblotting. Results: Higher levels of MCP-1, KC, IL-6 were induced in both ischemic and non-ischemic myocardium of old wild type mice at day 3 and 14 following ischemia/reperfusion (I/R) than those of adult wild type mice. The hyper-inflammatory responses to I/R in aging hearts were associated with elevated levels of myocardial TLR2. TLR2 KO markedly down-regulated the expression of MCP-1, KC, IL-6, ICAM-1 and VCAM-1 in aging hearts at day 3 and 14 following I/R. The down-regulated inflammatory activity in aging TLR2 KO hearts was associated with attenuated production of MMP 9 and collagen I at day 14 and resulted in reduced infarct size and improved cardiac function. Conclusion: Elevated expression of myocardial TLR2 contributes to the mechanism by which aging exacerbates the inflammatory responses, adverse remodeling and cardiac dysfunction following myocardial I/R in aging.
Assuntos
Cardiopatias , Traumatismo por Reperfusão , Envelhecimento/fisiologia , Animais , Colágeno , Infarto , Molécula 1 de Adesão Intercelular/genética , Molécula 1 de Adesão Intercelular/metabolismo , Interleucina-6 , Isquemia , Metaloproteinase 9 da Matriz , Camundongos , Camundongos Endogâmicos C57BL , Receptor 2 Toll-Like/metabolismo , Molécula 1 de Adesão de Célula VascularRESUMO
OBJECTIVE: Inflammatory infiltration in aortic valves promotes calcific aortic valve disease (CAVD) progression. While soluble extracellular matrix (ECM) proteins induce inflammatory responses in aortic valve interstitial cells (AVICs), the impact of monocytes on AVIC inflammatory responses is unknown. We tested the hypothesis that monocytes enhance AVIC inflammatory responses to soluble ECM protein in this study. METHODS: Human AVICs isolated from normal aortic valves were cocultured with monocytes and stimulated with soluble ECM protein (matrilin-2). ICAM-1 and IL-6 productions were assessed. YAP and NF-κB phosphorylation were analyzed. Recombinant CD18, neutralizing antibodies against ß2-integrin or ICAM-1, and inhibitor of YAP or NF-κB were applied. RESULTS: AVIC expression of ICAM-1 and IL-6 was markedly enhanced by the presence of monocytes, although matrilin-2 did not affect monocyte production of ICAM-1 or IL-6. Matrilin-2 up-regulated the expression of monocyte ß2-integrin and AVIC ICAM-1, leading to monocyte-AVIC adhesion. Neutralizing ß2-integrin or ICAM-1 in coculture suppressed monocyte adhesion to AVICs and the expression of ICAM-1 and IL-6. Recombinant CD18 enhanced the matrilin-2-induced ICAM-1 and IL-6 expression in AVIC monoculture. Further, stimulation of coculture with matrilin-2 induced greater YAP and NF-κB phosphorylation. Inhibiting either YAP or NF-κB markedly suppressed the inflammatory response to matrilin-2 in coculture. CONCLUSION: Monocyte ß2-integrin interacts with AVIC ICAM-1 to augment AVIC inflammatory responses to soluble matrilin-2 through enhancing the activation of YAP and NF-κB signaling pathways. Infiltrated monocytes may promote valvular inflammation through cell-cell interaction with AVICs to enhance their sensitivity to damage-associated molecular patterns.
Assuntos
Valva Aórtica , Monócitos , Valva Aórtica/metabolismo , Antígenos CD18/metabolismo , Células Cultivadas , Humanos , Molécula 1 de Adesão Intercelular/metabolismo , Interleucina-6/metabolismo , Proteínas Matrilinas/metabolismo , Monócitos/metabolismo , NF-kappa B/metabolismoRESUMO
BACKGROUND: Calcific aortic valve disease (CAVD) is the most prevalent heart valve disorder in the elderly. Valvular fibrocalcification is a characteristic pathological change. In diseased valves, monocyte accumulation is evident, and aortic valve interstitial cells (AVICs) display greater fibrogenic and osteogenic activities. However, the impact of activated monocytes on valular fibrocalcification remains unclear. We tested the hypothesis that pro-inflammatory mediators from activated monocytes elevate AVIC fibrogenic and osteogenic activities. METHODS AND RESULTS: Picro-sirius red staining and Alizarin red staining revealed collagen and calcium depositions in cultured human AVICs exposed to conditioned media derived from Pam3CSK4-stimulated monocytes (Pam3 CM). Pam3 CM up-regulated alkaline phosphatase (ALP), an osteogenic biomarker, and extracellular matrix proteins collagen I and matrix metalloproteinase-2 (MMP-2). ELISA analysis identified high levels of RANTES and TNF-α in Pam3 CM. Neutralizing RANTES in the Pam3 CM reduced its effect on collagen I and MMP-2 production in AVICs while neutralizing TNF-α attenuated the effect on AVIC ALP production. In addition, Pam3 CM induced NF-κB and JNK activation. While JNK mediated the effect of Pam3 CM on collagen I and MMP-2 production, NF-κB was critical for the effect of Pam3 CM on ALP production in AVICs. CONCLUSIONS: This study demonstrates that activated monocytes elevate the fibrogenic and osteogenic activities in human AVICs through a paracrine mechanism. TNF-α and RANTES mediate the pro-fibrogenic effect of activated monocytes on AVICs through activation of JNK, and TNF-α also activates NF-κB to elevate AVIC osteogenic activity. The results suggest that infiltrated monocytes elevate AVIC fibrocalcific activity to promote CAVD progression.
Assuntos
Estenose da Valva Aórtica/etiologia , Estenose da Valva Aórtica/metabolismo , Valva Aórtica/patologia , Calcinose/etiologia , Calcinose/metabolismo , Suscetibilidade a Doenças , Mediadores da Inflamação/metabolismo , Monócitos/metabolismo , Valva Aórtica/metabolismo , Biomarcadores , Células Cultivadas , Colágeno/metabolismo , Meios de Cultivo Condicionados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos BiológicosRESUMO
BACKGROUND: Aortic valve interstitial cells have been implicated in the pathogenesis of aortic stenosis. In response to proinflammatory stimuli, aortic valve interstitial cells undergo an osteogenic phenotypic change. The purpose of this study was to determine whether the anti-inflammatory effects of statins prevent osteogenic activity in cultured aortic valve interstitial cells. METHODS: Human aortic valve interstitial cells were isolated from hearts explanted for cardiac transplantation. To test whether simvastatin down-regulates TLR4-induced osteogenic response, aortic valve interstitial cells were treated with simvastatin with and without TLR4 agonist lipopolysaccharide (LPS), and osteogenic markers were measured. Simvastatin's influence on in vitro calcium deposition was assessed by alizarin red staining. Knockdown of postreceptor signaling proteins (MyD88 and TRIF) was performed to determine which of 2 TLR4-associated pathways mediates the osteogenic response. Expression levels of TLR4-induced nuclear factor kappa light chain enhancer of activated B cells (NF-κB) and TLR4 expression were assessed after treatment with simvastatin. Statistical testing was done by analysis of variance (P < .05). RESULTS: Simvastatin decreased LPS-induced ALP and Runx2 expression and inhibited in vitro calcium deposition in aortic valve interstitial cells. Knockdown of MyD88 and TRIF attenuated the osteogenic response. Simvastatin attenuated TLR4-dependent NF-κB signaling and down-regulated TLR4 levels. CONCLUSIONS: Simvastatin prevented TLR4-induced osteogenic phenotypic changes in isolated aortic valve interstitial cells via down-regulation of TLR4 and inhibition of NF-κB signaling. These data offer mechanistic insight into a possible therapeutic role for simvastatin in the prevention of aortic stenosis.
Assuntos
Valva Aórtica/efeitos dos fármacos , Valva Aórtica/patologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Osteogênese/efeitos dos fármacos , Sinvastatina/farmacologia , Proteínas Adaptadoras de Transporte Vesicular/fisiologia , Fosfatase Alcalina/metabolismo , Valva Aórtica/metabolismo , Técnicas de Cultura de Células , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Humanos , Lipopolissacarídeos/fisiologia , Fator 88 de Diferenciação Mieloide/fisiologia , NF-kappa B/metabolismo , Transdução de Sinais , Receptor 4 Toll-Like/fisiologiaRESUMO
BACKGROUND: Calcific aortic valve disease (CAVD) is a chronic inflammatory disease that manifests as progressive valvular fibrosis and calcification. An inflammatory milieu in valvular tissue promotes fibrosis and calcification. Aortic valve interstitial cell (AVIC) proliferation and the over-production of the extracellular matrix (ECM) proteins contribute to valvular thickening. However, the mechanism underlying elevated AVIC fibrogenic activity remains unclear. Recently, we observed that AVICs from diseased aortic valves express higher levels of neurotrophin 3 (NT3) and that NT3 exerts pro-osteogenic and pro-fibrogenic effects on human AVICs. HYPOTHESIS: Pro-inflammatory stimuli upregulate NT3 production in AVICs to promote fibrogenic activity in human aortic valves. METHODS AND RESULTS: AVICs were isolated from normal human aortic valves and were treated with lipopolysaccharide (LPS, 0.20 µg/mL). LPS induced TLR4-dependent NT3 production. This effect of LPS was abolished by inhibition of the Akt and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) pathways. The stimulation of TLR4 in human AVICs with LPS resulted in a greater proliferation rate and an upregulated production of matrix metallopeptidases-9 (MMP-9) and collagen III, as well as augmented collagen deposition. Recombinant NT3 promoted AVIC proliferation in a tropomyosin receptor kinase (Trk)-dependent fashion. The neutralization of NT3 or the inhibition of Trk suppressed LPS-induced AVIC fibrogenic activity. CONCLUSIONS: The stimulation of TLR4 in human AVICs upregulates NT3 expression and promotes cell proliferation and collagen deposition. The NT3-Trk cascade plays a critical role in the TLR4-mediated elevation of fibrogenic activity in human AVICs. Upregulated NT3 production by endogenous TLR4 activators may contribute to aortic valve fibrosis associated with CAVD progression.
Assuntos
Cardiopatias Congênitas/patologia , Doenças das Valvas Cardíacas/patologia , Neurotrofina 3/metabolismo , Receptor 4 Toll-Like/metabolismo , Valva Aórtica/citologia , Valva Aórtica/metabolismo , Valva Aórtica/patologia , Doença da Válvula Aórtica Bicúspide , Carbazóis/farmacologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Colágeno/metabolismo , Feminino , Cardiopatias Congênitas/metabolismo , Doenças das Valvas Cardíacas/metabolismo , Humanos , Alcaloides Indólicos/farmacologia , Lipopolissacarídeos/farmacologia , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Pessoa de Meia-Idade , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor trkA/antagonistas & inibidores , Receptor trkA/metabolismo , Transdução de Sinais/efeitos dos fármacos , Receptor 4 Toll-Like/genética , Regulação para Cima/efeitos dos fármacosRESUMO
OBJECTIVES: This study was to explore the prognostic value of connective tissue growth factor (CTGF) expression in endometrial cancer (EC). METHODS: We compared CTGF expression in 198 samples from patients with endometrial cancer and 50 samples from patients with healthy endometrial tissues as determined by immunohistochemistry. RESULTS: Expression of CTGF was significantly higher in endometrial cancers as compared to normal endometrial tissues. Positive CTGF expression displayed a strong association with CA125 level, histological grade, depth of myometrial invasion and the International Federation of Gynecology and Obstetrics (FIGO) stage. Our findings revealed histological grade, depth of myometrial invasion, FIGO stage, vascular/lymphatic invasion, and the CTGF expression are related to 5-year survival in patients with endometrial cancer. Positive CTGF expression, lymph node status, as well as vascular/lymphatic invasion, were identified as independent prognostic factors in endometrial cancer. CONCLUTIONS: Over-expression of CTGF is an independent prognostic factor that will allow the successful differentiation of high-risk population from the group of patients with stage III-IV endometrial cancer. The up-regulation of CTGF may contribute to the progression of endometrial cancer and serve as a new prognostic biomarker in patients with endometrial cancer survival.
Assuntos
Fator de Crescimento do Tecido Conjuntivo/metabolismo , Neoplasias do Endométrio/genética , Adulto , Idoso , Progressão da Doença , Neoplasias do Endométrio/patologia , Feminino , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Prognóstico , Adulto JovemRESUMO
BACKGROUND: Overproduction of extracellular matrix (ECM) protein by aortic valve interstitial cells (AVICs) plays an important role in valvular sclerosis (thickening) associated with the early pathobiology of aortic stenosis. Accumulation of oxidized low-density lipoprotein (oxLDL) is observed in sclerotic aortic valve and may have a mechanistic role in valvular disease progression. Lysophosphatidylcholine (LysoPC) is a component of oxLDL and has multiple biological activities. This study was to test the hypothesis that oxLDL and LysoPC upregulate ECM protein production in human AVICs. METHODS AND RESULTS: AVICs were isolated from normal human aortic valves. Cells were treated with oxLDL (40 µg/mL) or LysoPC (40 µmol/L). Immunoblotting was applied to analyze ECM proteins (collagens I and III and biglycan) in cell lysate and Picrosirius red staining was used to examine collagen deposition. Both oxLDL and LysoPC upregulated the production of biglycan and collagen I. The upregulation of ECM proteins by LysoPC was preceded by the phosphorylation of Akt and ERK1/2. Inhibition of Akt markedly reduced the effect of LysoPC on ECM protein production and collagen deposition. However, inhibition of ERK1/2 had no effect. CONCLUSIONS: LysoPC upregulates the production of biglycan and collagen I in human AVICs and may mediate the effect of oxLDL on ECM protein production. The Akt pathway appears to be critical in mediating the effect of LysoPC. oxLDL accumulation and generation of LysoPC in the aortic valve tissue may contribute to the mechanism of valvular sclerosis associated with the development and progression of aortic stenosis.
Assuntos
Estenose da Valva Aórtica/metabolismo , Valva Aórtica/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Lipoproteínas LDL/metabolismo , Lisofosfatidilcolinas/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Regulação para Cima , Idoso , Valva Aórtica/citologia , Biglicano/metabolismo , Biomarcadores/metabolismo , Células Cultivadas , Colágeno Tipo I/metabolismo , Colágeno Tipo III/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transdução de SinaisRESUMO
Elevated level of blood phosphate (Pi) associated with chronic kidney disease (CKD) is a risk factor of aortic valve calcification. Aortic valve interstitial cells (AVICs) display osteogenic responses to high Pi although the underlying mechanism is incompletely understood. Sox9 is a pro-chondrogenic factor and may play a role in ectopic tissue calcification. Circulating and kidney levels of Klotho are reduced in patients with CKD. We hypothesized that Sox9 mediates high Pi-induced osteogenic responses in human AVICs and that Klotho inhibits the responses. Treatment of human AVICs with high Pi increased protein levels of Runt-related transcription factor 2 (Runx2) and alkaline phosphatase (ALP), and a prolonged exposure to high Pi caused calcium deposition. High Pi induced Sox9 upregulation through PKD and Akt activation. Knockdown of Sox9 essentially abolished the effect of high Pi on the osteogenic responses. Lower Klotho levels were observed in calcified aortic valve tissues. Interestingly, high Pi decreased Klotho levels in AVICs from normal valves, and treatment with recombinant Klotho markedly reduced the effect of high Pi on the levels of Sox9, Runx2, and ALP and suppressed calcium deposition. We conclude that high Pi induces human AVIC osteogenic responses through Sox9. Human AVICs express Klotho, and its levels in AVICs are modulated by high Pi and valvular calcification. Importantly, Klotho suppresses the pro-osteogenic effect of high Pi on human AVICs. These novel findings indicate that modulation of Klotho may have therapeutic potential for mitigation of valvular calcification associated with CKD. KEY MESSAGES: CAVD associated with chronic kidney disease is a significant clinical problem. High phosphate upregulates Sox9 through AKT and PKD in human AVICs. Calcified human aortic valves have lower levels of Klotho. Klotho suppresses Sox9 upregulation and intranuclear translocation. Klotho inhibits high phosphate-induced osteogenic activity in human AVICs.
Assuntos
Valva Aórtica/citologia , Glucuronidase/metabolismo , Osteogênese , Fosfatos/metabolismo , Fatores de Transcrição SOX9/metabolismo , Animais , Valva Aórtica/metabolismo , Valva Aórtica/patologia , Estenose da Valva Aórtica/genética , Estenose da Valva Aórtica/metabolismo , Calcinose/genética , Calcinose/metabolismo , Células Cultivadas , Regulação para Baixo , Humanos , Proteínas Klotho , Proteína Quinase C/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fatores de Transcrição SOX9/genética , Transdução de SinaisRESUMO
Calcific aortic valve disease (CAVD) is a leading cardiovascular disorder in the elderly. Diseased aortic valves are characterized by sclerosis (fibrosis) and nodular calcification. Sclerosis, an early pathological change, is caused by aortic valve interstitial cell (AVIC) proliferation and overproduction of extracellular matrix (ECM) proteins. However, the mechanism of aortic valve sclerosis remains unclear. Recently, we observed that diseased human aortic valves overexpress growth factor neurotrophin 3 (NT3). In the present study, we tested the hypothesis that NT3 is a profibrogenic factor to human AVICs. AVICs isolated from normal human aortic valves were cultured in M199 growth medium and treated with recombinant human NT3 (0.10 µg/ml). An exposure to NT3 induced AVIC proliferation, upregulated the production of collagen and matrix metalloproteinase (MMP), and augmented collagen deposition. These changes were abolished by inhibition of the Trk receptors. NT3 induced Akt phosphorylation and increased cyclin D1 protein levels in a Trk receptor-dependent fashion. Inhibition of Akt abrogated the effect of NT3 on cyclin D1 production. Furthermore, inhibition of either Akt or cyclin D1 suppressed NT3-induced cellular proliferation and MMP-9 and collagen production, as well as collagen deposition. Thus, NT3 upregulates cellular proliferation, ECM protein production, and collagen deposition in human AVICs. It exerts these effects through the Trk-Akt-cyclin D1 cascade. NT3 is a profibrogenic mediator in human aortic valve, and overproduction of NT3 by aortic valve tissue may contribute to the mechanism of valvular sclerosis.
Assuntos
Estenose da Valva Aórtica/genética , Valva Aórtica/patologia , Calcinose/genética , Colágeno/genética , Ciclina D1/genética , Metaloproteinases da Matriz/genética , Neurotrofina 3/farmacologia , Proteínas Proto-Oncogênicas c-akt/genética , Receptor trkA/genética , Idoso , Valva Aórtica/metabolismo , Valva Aórtica/cirurgia , Estenose da Valva Aórtica/metabolismo , Estenose da Valva Aórtica/patologia , Estenose da Valva Aórtica/cirurgia , Calcinose/metabolismo , Calcinose/patologia , Calcinose/cirurgia , Estudos de Casos e Controles , Proliferação de Células/efeitos dos fármacos , Colágeno/biossíntese , Ciclina D1/metabolismo , Feminino , Regulação da Expressão Gênica , Humanos , Masculino , Metaloproteinases da Matriz/biossíntese , Pessoa de Meia-Idade , Miofibroblastos/citologia , Miofibroblastos/efeitos dos fármacos , Miofibroblastos/metabolismo , Neurotrofina 3/genética , Neurotrofina 3/metabolismo , Cultura Primária de Células , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor trkA/antagonistas & inibidores , Receptor trkA/metabolismo , Esclerose , Transdução de Sinais , Substituição da Valva Aórtica TranscateterRESUMO
UNLABELLED: Calcific aortic valve disease (CAVD) is characterized by chronic inflammation and progressive calcification in valve leaflets. Aortic valve interstitial cells (AVICs) play a critical role in the pathogenesis of CAVD. Previous studies show that stimulation of Toll-like receptor (TLR) 2 or TLR4 in AVICs in vitro up-regulates the expression of osteogenic mediators. Double-stranded RNA (dsRNA) can activate pro-inflammatory signaling through TLR3, the NLRP3 inflammasome and RIG-I-like receptors. The objective of this study is to determine the effect of dsRNA on AVIC osteogenic activities and the mechanism of its action. METHODS AND RESULTS: AVICs isolated from normal human valves were exposed to polyinosinic-polycytidylic acid [poly(I:C)], a mimic of dsRNA. Treatment with poly(I:C) increased the production of bone morphogenetic protein-2 (BMP-2), transforming growth factor beta-1 (TGF-ß1) and alkaline phosphatase (ALP), and resulted in calcium deposit formation. Poly(I:C) induced the phosphorylation of NF-κB and ERK1/2. Knockdown of TLR3 essentially abrogated NF-κB and ERK1/2 phosphorylation, and markedly reduced the effect of poly(I:C) on the production of BMP-2, TGF-ß1 and ALP. Further, inhibition of either NF-κB or ERK1/2 markedly reduced the levels of BMP-2, TGF-ß1 and ALP in cells exposed to poly(I:C). CONCLUSION: Poly(I:C) up-regulates the production of BMP-2, TGF-ß1 and ALP, and promotes calcium deposit formation in human AVICs. The pro-osteogenic effect of poly(I:C) is mediated primarily by TLR3 and the NF-κB and ERK1/2 pathways. These findings suggest that dsRNA, when present in aortic valve tissue, may promote CAVD progression through up-regulation of AVIC osteogenic activities.