RESUMO
AIMS: The metabolic failure of macrophages to adequately process lipid is central to the aetiology of atherosclerosis. Here, we examine the role of macrophage angiotensin-converting enzyme (ACE) in a mouse model of PCSK9-induced atherosclerosis. METHODS AND RESULTS: Atherosclerosis in mice was induced with AAV-PCSK9 and a high-fat diet. Animals with increased macrophage ACE (ACE 10/10 mice) have a marked reduction in atherosclerosis vs. WT mice. Macrophages from both the aorta and peritoneum of ACE 10/10 express increased PPARα and have a profoundly altered phenotype to process lipids characterized by higher levels of the surface scavenger receptor CD36, increased uptake of lipid, increased capacity to transport long chain fatty acids into mitochondria, higher oxidative metabolism and lipid ß-oxidation as determined using 13C isotope tracing, increased cell ATP, increased capacity for efferocytosis, increased concentrations of the lipid transporters ABCA1 and ABCG1, and increased cholesterol efflux. These effects are mostly independent of angiotensin II. Human THP-1 cells, when modified to express more ACE, increase expression of PPARα, increase cell ATP and acetyl-CoA, and increase cell efferocytosis. CONCLUSION: Increased macrophage ACE expression enhances macrophage lipid metabolism, cholesterol efflux, efferocytosis, and it reduces atherosclerosis. This has implications for the treatment of cardiovascular disease with angiotensin II receptor antagonists vs. ACE inhibitors.
Assuntos
Aterosclerose , Pró-Proteína Convertase 9 , Humanos , Animais , Camundongos , Pró-Proteína Convertase 9/metabolismo , PPAR alfa/genética , PPAR alfa/metabolismo , Metabolismo dos Lipídeos , Colesterol/metabolismo , Macrófagos/metabolismo , Aterosclerose/genética , Aterosclerose/prevenção & controle , Angiotensinas/metabolismo , Trifosfato de Adenosina/metabolismo , Transportador 1 de Cassete de Ligação de ATP/genética , Transportador 1 de Cassete de Ligação de ATP/metabolismoRESUMO
Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive disease with poor prognosis, which is mainly due to drug resistance. The biology determining the response to chemo-radiotherapy in HNSCC is poorly understood. Using clinical samples, we found that miR124-3p and miR766-3p are overexpressed in chemo-radiotherapy-resistant (non-responder) HNSCC, as compared to responder tumors. Our study shows that inhibition of miR124-3p and miR766-3p enhances the sensitivity of HNSCC cell lines, CAL27 and FaDu, to 5-fluorouracil and cisplatin (FP) chemotherapy and radiotherapy. In contrast, overexpression of miR766-3p and miR124-3p confers a resistance phenotype in HNSCC cells. The upregulation of miR124-3p and miR766-3p is associated with increased HNSCC cell invasion and migration. In a xenograft mouse model, inhibition of miR124-3p and miR766-3p enhanced the efficacy of chemo-radiotherapy with reduced growth of resistant HNSCC. For the first time, we identified that miR124-3p and miR766-3p attenuate expression of CREBRF and NR3C2, respectively, in HNSCC, which promotes aggressive tumor behavior by inducing the signaling axes CREB3/ATG5 and ß-catenin/c-Myc. Since miR124-3p and miR766-3p affect complementary pathways, combined inhibition of these two miRNAs shows an additive effect on sensitizing cancer cells to chemo-radiotherapy. In conclusion, our study demonstrated a novel miR124-3p- and miR766-3p-based biological mechanism governing treatment-resistant HNSCC, which can be targeted to improve clinical outcomes in HNSCC.
RESUMO
BACKGROUND: Chronic renal inflammation has been widely recognized as a major promoter of several forms of high blood pressure including salt-sensitive hypertension. In diabetes, IL (interleukin)-6 induces salt sensitivity through a dysregulation of the epithelial sodium channel. However, the origin of this inflammatory process and the molecular events that culminates with an abnormal regulation of epithelial sodium channel and salt sensitivity in diabetes are largely unknown. METHODS: Both in vitro and in vivo approaches were used to investigate the molecular and cellular contributors to the renal inflammation associated with diabetic kidney disease and how these inflammatory components interact to develop salt sensitivity in db/db mice. RESULTS: Thirty-four-week-old db/db mice display significantly higher levels of IL-1ß in renal tubules compared with nondiabetic db/+ mice. Specific suppression of IL-1ß in renal tubules prevented salt sensitivity in db/db mice. A primary culture of renal tubular epithelial cells from wild-type mice releases significant levels of IL-1ß when exposed to a high glucose environment. Coculture of tubular epithelial cells and bone marrow-derived macrophages revealed that tubular epithelial cell-derived IL-1ß promotes the polarization of macrophages towards a proinflammatory phenotype resulting in IL-6 secretion. To evaluate whether macrophages are the cellular target of IL-1ß in vivo, diabetic db/db mice were transplanted with the bone marrow of IL-1R1 (IL-1 receptor type 1) knockout mice. db/db mice harboring an IL-1 receptor type 1 knockout bone marrow remained salt resistant, display lower renal inflammation and lower expression and activity of epithelial sodium channel compared with db/db transplanted with a wild-type bone marrow. CONCLUSIONS: Renal tubular epithelial cell-derived IL-1ß polarizes renal macrophages towards a proinflammatory phenotype that promotes salt sensitivity through the accumulation of renal IL-6. When tubular IL-1ß synthesis is suppressed or in db/db mice in which immune cells lack the IL-1R1, macrophage polarization is blunted resulting in no salt-sensitive hypertension.
Assuntos
Diabetes Mellitus , Nefropatias Diabéticas , Hipertensão , Nefrite , Animais , Diabetes Mellitus/metabolismo , Nefropatias Diabéticas/genética , Canais Epiteliais de Sódio/genética , Canais Epiteliais de Sódio/metabolismo , Inflamação/metabolismo , Interleucina-6/metabolismo , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Nefrite/metabolismo , Receptores de Interleucina-1/metabolismo , Cloreto de Sódio na Dieta/toxicidadeRESUMO
Kidneys continuously filter an enormous amount of sodium and adapt kidney Na+ reabsorption to match Na+ intake to maintain circulatory volume and electrolyte homeostasis. Males (M) respond to high-salt (HS) diet by translocating proximal tubule Na+/H+ exchanger isoform 3 (NHE3) to the base of the microvilli, reducing activated forms of the distal NaCl cotransporter (NCC) and epithelial Na+ channel (ENaC). Males (M) and females (F) on normal-salt (NS) diet present sex-specific profiles of "transporters" (cotransporters, channels, pumps, and claudins) along the nephron, e.g., F exhibit 40% lower NHE3 and 200% higher NCC abundance than M. We tested the hypothesis that adaptations to HS diet along the nephron will, likewise, exhibit sexual dimorphisms. C57BL/6J mice were fed for 15 days with 4% NaCl diet (HS) versus 0.26% NaCl diet (NS). On HS, M and F exhibited normal plasma [Na+] and [K+], similar urine volume, Na+, K+, and osmolal excretion rates normalized to body weight. In F, like M, HS lowered abundance of distal NCC, phosphorylated NCC, and cleaved (activated) forms of ENaC. The adaptations associated with achieving electrolyte homeostasis exhibit sex-dependent and independent mechanisms. Sex differences in baseline "transporters" abundance persist during HS diet, yet the fold changes during HS diet (normalized to NS) are similar along the distal nephron and collecting duct. Sex-dependent differences observed along the proximal tubule during HS show that female kidneys adapt differently from patterns reported in males, yet achieve and maintain fluid and electrolyte homeostasis.
Assuntos
Adaptação Fisiológica , Proteínas de Membrana Transportadoras/metabolismo , Néfrons/metabolismo , Cloreto de Sódio na Dieta/metabolismo , Equilíbrio Hidroeletrolítico , Animais , Biomarcadores/sangue , Biomarcadores/urina , Feminino , Túbulos Renais Coletores/metabolismo , Túbulos Renais Proximais/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Fosforilação , Caracteres Sexuais , Fatores Sexuais , Cloreto de Sódio na Dieta/efeitos adversos , Trocador 3 de Sódio-Hidrogênio/metabolismo , Membro 1 da Família 12 de Carreador de Soluto/metabolismo , Membro 3 da Família 12 de Carreador de Soluto/metabolismoRESUMO
Angiotensin-converting enzyme inhibitors (ACEIs) are used by millions of patients to treat hypertension, diabetic kidney disease, and heart failure. However, these patients are often at increased risk of infection. To evaluate the impact of ACEIs on immune responses to infection, we compared the effect of an ACEI versus an angiotensin receptor blocker (ARB) on neutrophil antibacterial activity. ACEI exposure reduced the ability of murine neutrophils to kill methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumoniae in vitro. In vivo, ACEI-treated mice infected with MRSA had increased bacteremia and tissue bacteria counts compared to mice treated with an ARB or with no drug. Similarly, ACEIs, but not ARBs, increased the incidence of MRSA-induced infective endocarditis in mice with aortic valve injury. Neutrophils from ACE knockout (KO) mice or mice treated with an ACEI produced less leukotriene B4 (LTB4) upon stimulation with MRSA or lipopolysaccharide, whereas neutrophils overexpressing ACE produced more LTB4 compared to wild-type neutrophils. As a result of reduced LTB4 production, ACE KO neutrophils showed decreased survival signaling and increased apoptosis. In contrast, neutrophils overexpressing ACE had an enhanced survival phenotype. Last, in a cohort of human volunteers receiving the ACEI ramipril for 1 week, ACEI administration reduced neutrophil superoxide and reactive oxygen species production and neutrophils isolated from volunteers during ramipril treatment had reduced bactericidal activity. Together, these data demonstrate that ACEI treatment, but not ARB treatment, can reduce the bacterial killing ability of neutrophils.
Assuntos
Inibidores da Enzima Conversora de Angiotensina , Staphylococcus aureus Resistente à Meticilina , Antagonistas de Receptores de Angiotensina/farmacologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Animais , Humanos , Camundongos , Camundongos Knockout , NeutrófilosAssuntos
Caseínas , Sódio , Animais , Dieta , Canais Epiteliais de Sódio , Rim/metabolismo , Ratos , Sódio/metabolismoRESUMO
BACKGROUND: Hypertension is considered a major risk factor for the progression of diabetic kidney disease. Type 2 diabetes is associated with increased renal sodium reabsorption and salt-sensitive hypertension. Clinical studies show that men have higher risk than premenopausal women for the development of diabetic kidney disease. However, the renal mechanisms that predispose to salt sensitivity during diabetes and whether sexual dimorphism is associated with these mechanisms remains unknown. METHODS: Female and male db/db mice exposed to a high-salt diet were used to analyze the progression of diabetic kidney disease and the development of hypertension. RESULTS: Male, 34-week-old, db/db mice display hypertension when exposed to a 4-week high-salt treatment, whereas equivalently treated female db/db mice remain normotensive. Salt-sensitive hypertension in male mice was associated with no suppression of the epithelial sodium channel (ENaC) in response to a high-salt diet, despite downregulation of several components of the intrarenal renin-angiotensin system. Male db/db mice show higher levels of proinflammatory cytokines and more immune-cell infiltration in the kidney than do female db/db mice. Blocking inflammation, with either mycophenolate mofetil or by reducing IL-6 levels with a neutralizing anti-IL-6 antibody, prevented the development of salt sensitivity in male db/db mice. CONCLUSIONS: The inflammatory response observed in male, but not in female, db/db mice induces salt-sensitive hypertension by impairing ENaC downregulation in response to high salt. These data provide a mechanistic explanation for the sexual dimorphism associated with the development of diabetic kidney disease and salt sensitivity.
Assuntos
Diabetes Mellitus Tipo 2/etiologia , Canais Epiteliais de Sódio/fisiologia , Hipertensão/etiologia , Cloreto de Sódio na Dieta/administração & dosagem , Animais , Citocinas/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Modelos Animais de Doenças , Feminino , Hipertensão/metabolismo , Hipertensão/patologia , Inflamação , Masculino , Camundongos , Fatores Sexuais , Cloreto de Sódio na Dieta/efeitos adversosRESUMO
The observation that all components of the renin angiotensin system (RAS) are expressed in the kidney and the fact that intratubular angiotensin (Ang) II levels greatly exceed the plasma concentration suggest that the synthesis of renal Ang II occurs independently of the circulating RAS. One of the main components of this so-called intrarenal RAS is angiotensin-converting enzyme (ACE). Although the role of ACE in renal disease is demonstrated by the therapeutic effectiveness of ACE inhibitors in treating several conditions, the exact contribution of intrarenal versus systemic ACE in renal disease remains unknown. Using genetically modified mouse models, our group demonstrated that renal ACE plays a key role in the development of several forms of hypertension. Specifically, although ACE is expressed in different cell types within the kidney, its expression in renal proximal tubular cells is essential for the development of high blood pressure. Besides hypertension, ACE is involved in several other renal diseases such as diabetic kidney disease, or acute kidney injury even when blood pressure is normal. In addition, studies suggest that ACE might mediate at least part of its effect through mechanisms that are independent of the Ang I conversion into Ang II and involve other substrates such as N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP), Ang-(1-7), and bradykinin, among others. In this review, we summarize the recent advances in understanding the contribution of intrarenal ACE to different pathological conditions and provide insight into the many roles of ACE besides the well-known synthesis of Ang II.
Assuntos
Injúria Renal Aguda/enzimologia , Angiotensina I/metabolismo , Nefropatias Diabéticas/enzimologia , Hipertensão/enzimologia , Fragmentos de Peptídeos/metabolismo , Peptidil Dipeptidase A/metabolismo , Sistema Renina-Angiotensina/genética , Injúria Renal Aguda/genética , Injúria Renal Aguda/patologia , Angiotensina I/genética , Angiotensina II/genética , Angiotensina II/metabolismo , Animais , Pressão Sanguínea/genética , Bradicinina/metabolismo , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , Regulação da Expressão Gênica , Humanos , Hipertensão/genética , Hipertensão/patologia , Rim/enzimologia , Rim/patologia , Camundongos , Oligopeptídeos/metabolismo , Fragmentos de Peptídeos/genética , Peptidil Dipeptidase A/genética , Transdução de Sinais , Equilíbrio Hidroeletrolítico/genéticaRESUMO
Granulocytes are key players in cancer metastasis. While tumor-induced de novo expansion of immunosuppressive myeloid-derived suppressor cells (MDSCs) is well-described, the fate and contribution of terminally differentiated mature neutrophils to the metastatic process remain poorly understood. Here, we show that in experimental metastatic cancer models, CXCR4hiCD62Llo aged neutrophils accumulate via disruption of neutrophil circadian homeostasis and direct stimulation of neutrophil aging mediated by angiotensin II. Compared to CXCR4loCD62Lhi naive neutrophils, aged neutrophils more robustly promote tumor migration and support metastasis through the increased release of several metastasis-promoting factors, including neutrophil extracellular traps (NETs), reactive oxygen species, vascular endothelial growth factors, and metalloproteinases (MMP-9). Adoptive transfer of aged neutrophils significantly enhanced metastasis of breast (4T1) and melanoma (B16LS9) cancer cells to the liver, and these effects were predominantly mediated by NETs. Our results highlight that in addition to modulating MDSC production, targeting aged neutrophil clearance and homeostasis may be effective in reducing cancer metastasis.
Assuntos
Armadilhas Extracelulares , Melanoma , Células Supressoras Mieloides , Idoso , Granulócitos , Humanos , Selectina L , Neutrófilos , Receptores CXCR4RESUMO
BACKGROUND AND PURPOSE: The AT2 receptor plays a role in metabolism by opposing the actions triggered by the AT1 receptors. Activation of AT2 receptors has been shown to enhance insulin sensitivity in both normal and insulin resistance animal models. In this study, we investigated the mechanism by which AT2 receptors activation improves metabolism in diabetic mice. EXPERIMENTAL APPROACH: Female diabetic (db/db) and non-diabetic (db/+) mice were treated for 1 month with the selective AT2 agonist, compound 21 (C21, 0.3 mg·kg-1 ·day-1 , s.c.). To evaluate whether the effects of C21 depend on NO production, a subgroup of mice was treated with C21 plus a sub-pressor dose of the NOS inhibitor l-NAME (0.1 mg·ml-1 , drinking water). KEY RESULTS: C21-treated db/db mice displayed improved glucose and pyruvate tolerance compared with saline-treated db/db mice. Also, C21-treated db/db mice showed reduced liver weight and decreased hepatic lipid accumulation compared with saline-treated db/db mice. Insulin signalling analysis showed increased phosphorylation of the insulin receptor, Akt and FOXO1 in the livers of C21-treated db/db mice compared with saline-treated counterparts. These findings were associated with increased adiponectin levels in plasma and adipose tissue and reduced adipocyte size in inguinal fat. The beneficial effects of AT2 receptors activation were associated with increased eNOS phosphorylation and higher levels of NO metabolites and were abolished by l-NAME. CONCLUSION AND IMPLICATIONS: Chronic C21 infusion exerts beneficial metabolic effects in female diabetic db/db mice, alleviating type 2 diabetes complications, through a mechanism that involves NO production.
Assuntos
Complicações do Diabetes , Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Animais , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Receptor Tipo 2 de AngiotensinaRESUMO
Angiotensin-converting enzyme (ACE), a dicarboxypeptidase, plays a major role in the regulation of blood pressure by cleaving angiotensin I into angiotensin II (Ang II), a potent vasoconstrictor. Because of its wide substrate specificity and tissue distribution, ACE affects many diverse biological processes. In inflammatory diseases, including granuloma, atherosclerosis, chronic kidney disease and bacterial infection, ACE expression gets upregulated in immune cells, especially in myeloid cells. With increasing evidences connecting ACE functions to the pathogenesis of these acquired diseases, it is suggested that ACE plays a vital role in immune functions. Recent studies with mouse models of bacterial infection and tumor suggest that ACE plays an important role in the immune responses of myeloid cells. Inhibition of ACE suppresses neutrophil immune response to bacterial infection. In contrast, ACE overexpression in myeloid cells strongly induced bacterial and tumor resistance in mice. A detailed biochemical understanding of how ACE activates myeloid cells and which ACE peptide(s) (substrate or product) mediate these effects could lead to the development of novel therapies for boosting immunity against a variety of stimuli, including bacterial infection and tumor.
Assuntos
Hematopoese/imunologia , Inflamação/imunologia , Células Mieloides/imunologia , Peptidil Dipeptidase A/fisiologia , Imunidade Adaptativa , Animais , Infecções Bacterianas/imunologia , Humanos , Camundongos , Neoplasias/imunologia , Peptidil Dipeptidase A/imunologiaRESUMO
PURPOSE OF REVIEW: To review recent studies exploring how myeloid cell overexpression of angiotensin-converting enzyme (ACE) affects the immune response and to formulate an approach for considering the effectiveness of inflammation in cardiovascular disease RECENT FINDINGS: While it is widely appreciated that the renin-angiotensin system affects aspects of inflammation through the action of angiotensin II, new studies reveal a previously unknown role of ACE in myeloid cell biology. This was apparent from analysis of two mouse lines genetically modified to overexpress ACE in monocytes/macrophages or neutrophils. Cells overexpressing ACE demonstrated an increased immune response. For example, mice with increased macrophage ACE expression have increased resistance to melanoma, methicillin-resistant Staphylococcus aureus, a mouse model of Alzheimer's disease, and ApoE-knockout-induced atherosclerosis. These data indicate the profound effect of increasing myeloid cell function. Further, they suggest that an appropriate way to evaluate inflammation in both acute and chronic diseases is to ask whether the inflammatory infiltrate is sufficient to eliminate the immune challenge. The expression of ACE by myeloid cells induces a heightened immune response by these cells. The overexpression of ACE is associated with immune function beyond that possible by wild type (WT) myeloid cells. A heightened immune response effectively resolves disease in a variety of acute and chronic models of disease including models of Alzheimer's disease and atherosclerosis.
Assuntos
Hipertensão , Inflamação , Staphylococcus aureus Resistente à Meticilina , Peptidil Dipeptidase A , Animais , Doença Crônica , Humanos , Camundongos , Células Mieloides , Peptidil Dipeptidase A/metabolismoRESUMO
AIM: Sexual dimorphisms are evident along the nephron: Females (F) exhibit higher ratios of renal distal to proximal Na+ transporters' abundance, greater lithium clearance (CLi ) more rapid natriuresis in response to saline infusion and lower plasma [K+ ] vs. males (M). During angiotensin II infusion hypertension (AngII-HTN) M exhibit distal Na+ transporter activation, lower proximal and medullary loop transporters, blunted natriuresis in response to saline load, and reduced plasma [K+ ]. This study aimed to determine whether responses of F to AngII-HTN mimicked those in M or were impacted by sexual dimorphisms evident at baseline. METHODS: Sprague Dawley rats and C57BL/6 mice were AngII infused via osmotic minipumps 2 and 3 weeks, respectively, and assessed by metabolic cage collections, tail-cuff sphygmomanometer, semi-quantitative immunoblotting of kidney and patch-clamp electrophysiology. RESULTS: In F rats, AngII-infusion increased BP to 190 mm Hg, increased phosphorylation of cortical NKCC2, NCC and cleavage of ENaC two to threefold, increased ENaC channel activity threefold and aldosterone 10-fold. K+ excretion increased and plasma [K+ ] decreased. Evidence of natriuresis in F included increased urine Na+ excretion and CLi , and decreased medullary NHE3, NKCC2 and Na,K-ATPase abundance. In C57BL/6 mice, AngII-HTN increased abundance of distal Na+ transporters, suppressed proximal-medullary transporters and reduced plasma [K+ ] in both F and M. CONCLUSION: Despite baseline sexual dimorphisms, AngII-HTN provokes similar increases in BP, aldosterone, distal transporters, ENaC channel activation and K+ loss accompanied by similar suppression of proximal and loop Na+ transporters, natriuresis and diuresis in females and males.
Assuntos
Angiotensina II/farmacologia , Eletrólitos/metabolismo , Hipertensão/metabolismo , Canais Iônicos/metabolismo , Animais , Canais Epiteliais de Sódio/metabolismo , Feminino , Hipertensão/induzido quimicamente , Transporte de Íons , Rim/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Técnicas de Patch-Clamp , Potássio/metabolismo , Ratos , Ratos Sprague-Dawley , Sódio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismoRESUMO
Angiotensin-converting enzyme (ACE) affects blood pressure. In addition, ACE overexpression in myeloid cells increases their immune function. Using MS and chemical analysis, we identified marked changes of intermediate metabolites in ACE-overexpressing macrophages and neutrophils, with increased cellular ATP (1.7-3.0-fold) and Krebs cycle intermediates, including citrate, isocitrate, succinate, and malate (1.4-3.9-fold). Increased ATP is due to ACE C-domain catalytic activity; it is reversed by an ACE inhibitor but not by an angiotensin II AT1 receptor antagonist. In contrast, macrophages from ACE knockout (null) mice averaged only 28% of the ATP levels found in WT mice. ACE overexpression does not change cell or mitochondrial size or number. However, expression levels of the electron transport chain proteins NDUFB8 (complex I), ATP5A, and ATP5ß (complex V) are significantly increased in macrophages and neutrophils, and COX1 and COX2 (complex IV) are increased in macrophages overexpressing ACE. Macrophages overexpressing ACE have increased mitochondrial membrane potential (24% higher), ATP production rates (29% higher), and maximal respiratory rates (37% higher) compared with WT cells. Increased cellular ATP underpins increased myeloid cell superoxide production and phagocytosis associated with increased ACE expression. Myeloid cells overexpressing ACE indicate the existence of a novel pathway in which myeloid cell function can be enhanced, with a key feature being increased cellular ATP.
Assuntos
Trifosfato de Adenosina/metabolismo , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Células Mieloides/metabolismo , Peptidil Dipeptidase A/metabolismo , Animais , Ciclo do Ácido Cítrico , Ciclo-Oxigenase 1/metabolismo , Ciclo-Oxigenase 2/metabolismo , Complexo I de Transporte de Elétrons/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Neutrófilos/metabolismo , Oxirredução , Estresse Oxidativo , Peptidil Dipeptidase A/genética , Regulação para CimaRESUMO
BACKGROUND: Macrophages are ubiquitous in all stages of atherosclerosis, exerting tremendous impact on lesion progression and plaque stability. Because macrophages in atherosclerotic plaques express angiotensin-converting enzyme (ACE), current dogma posits that local myeloid-mediated effects worsen the disease. In contrast, we previously reported that myeloid ACE overexpression augments macrophage resistance to various immune challenges, including tumors, bacterial infection and Alzheimer's plaque deposition. Here, we sought to assess the impact of myeloid ACE on atherosclerosis. METHODS: A mouse model in which ACE is overexpressed in myelomonocytic lineage cells, called ACE10, was generated and sequentially crossed with ApoE-deficient mice to create ACE10/10ApoE-/- (ACE10/ApoE). Control mice were ACEWT/WTApoE-/- (WT/ApoE). Atherosclerosis was induced using an atherogenic diet alone, or in combination with unilateral nephrectomy plus deoxycorticosterone acetate (DOCA) salt for eight weeks. RESULTS: With an atherogenic diet alone or in combination with DOCA, the ACE10/ApoE mice showed significantly less atherosclerotic plaques compared to their WT/ApoE counterparts (pâ¯<â¯0.01). When recipient ApoE-/- mice were reconstituted with ACE10/10 bone marrow, these mice showed significantly reduced lesion areas compared to recipients reconstituted with wild type bone marrow. Furthermore, transfer of ACE-deficient bone marrow had no impact on lesion area. CONCLUSION: Our data indicate that while myeloid ACE may not be required for atherosclerosis, enhanced ACE expression paradoxically reduced disease progression.
Assuntos
Aterosclerose/enzimologia , Aterosclerose/prevenção & controle , Células Mieloides/enzimologia , Peptidil Dipeptidase A/metabolismo , Animais , Aterosclerose/genética , Pressão Sanguínea , Transplante de Medula Óssea , Linhagem da Célula/genética , Colesterol/sangue , Dieta Aterogênica , Modelos Animais de Doenças , Progressão da Doença , Humanos , Macrófagos/enzimologia , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout para ApoE , Células Mieloides/patologia , Peptidil Dipeptidase A/genética , Regulação para CimaRESUMO
Angiotensin-converting enzyme (ACE) can hydrolyze many peptides and plays a central role in controlling blood pressure. Moreover, ACE overexpression in monocytes and macrophages increases resistance of mice to tumor growth. ACE is composed of two independent catalytic domains. Here, to investigate the specific role of each domain in tumor resistance, we overexpressed either WT ACE (Tg-ACE mice) or ACE lacking N- or C-domain catalytic activity (Tg-NKO and Tg-CKO mice) in the myeloid cells of mice. Tg-ACE and Tg-NKO mice exhibited strongly suppressed growth of B16-F10 melanoma because of increased ACE expression in macrophages, whereas Tg-CKO mice resisted melanoma no better than WT animals. The effect of ACE overexpression reverted to that of the WT enzyme with an ACE inhibitor but not with an angiotensin II type 1 (AT1) receptor antagonist. ACE C-domain overexpression in macrophages drove them toward a pronounced M1 phenotype upon tumor stimulation, with increased activation of NF-κB and signal transducer and activator of transcription 1 (STAT1) and decreased STAT3 and STAT6 activation. Tumor necrosis factor α (TNFα) is important for M1 activation, and TNFα blockade reverted Tg-NKO macrophages to a WT phenotype. Increased ACE C-domain expression increased the levels of reactive oxygen species (ROS) and of the transcription factor C/EBPß in macrophages, important stimuli for TNFα expression, and decreased expression of several M2 markers, including interleukin-4Rα. Natural ACE C-domain-specific substrates are not well-described, and we propose that the peptide(s) responsible for the striking ACE-mediated enhancement of myeloid function are substrates/products of the ACE C-domain.
Assuntos
Polaridade Celular , Macrófagos/citologia , Melanoma Experimental/patologia , Peptidil Dipeptidase A/metabolismo , Animais , Catálise , Linhagem Celular Tumoral , Sobrevivência Celular , Regulação Neoplásica da Expressão Gênica , Macrófagos/imunologia , Melanoma Experimental/enzimologia , Melanoma Experimental/genética , Melanoma Experimental/imunologia , Camundongos , Camundongos Transgênicos , NF-kappa B/metabolismo , Peptidil Dipeptidase A/química , Fator de Transcrição STAT1/metabolismo , Fator de Necrose Tumoral alfa/biossínteseRESUMO
BACKGROUND: Recent evidence emphasizes the critical role of inflammation in the development of diabetic nephropathy. Angiotensin-converting enzyme (ACE) plays an active role in regulating the renal inflammatory response associated with diabetes. Studies have also shown that ACE has roles in inflammation and the immune response that are independent of angiotensin II. ACE's two catalytically independent domains, the N- and C-domains, can process a variety of substrates other than angiotensin I. METHODS: To examine the relative contributions of each ACE domain to the sodium retentive state, renal inflammation, and renal injury associated with diabetic kidney disease, we used streptozotocin to induce diabetes in wild-type mice and in genetic mouse models lacking either a functional ACE N-domain (NKO mice) or C-domain (CKO mice). RESULTS: In response to a saline challenge, diabetic NKO mice excreted 32% more urinary sodium compared with diabetic wild-type or CKO mice. Diabetic NKO mice also exhibited 55% less renal epithelial sodium channel cleavage (a marker of channel activity), 55% less renal IL-1ß, 53% less renal TNF-α, and 53% less albuminuria than diabetic wild-type mice. This protective phenotype was not associated with changes in renal angiotensin II levels. Further, we present evidence that the anti-inflammatory tetrapeptide N-acetyl-seryl-asparyl-lysyl-proline (AcSDKP), an ACE N-domain-specific substrate that accumulates in the urine of NKO mice, mediates the beneficial effects observed in the NKO. CONCLUSIONS: These data indicate that increasing AcSDKP by blocking the ACE N-domain facilitates sodium excretion and ameliorates diabetic kidney disease independent of intrarenal angiotensin II regulation.
Assuntos
Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Peptidil Dipeptidase A/química , Peptidil Dipeptidase A/deficiência , Substituição de Aminoácidos , Angiotensina II/metabolismo , Animais , Domínio Catalítico/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Nefropatias Diabéticas/genética , Canais Epiteliais de Sódio/metabolismo , Inflamação/genética , Inflamação/metabolismo , Inflamação/patologia , Interleucina-1beta/metabolismo , Rim/metabolismo , Rim/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutagênese Sítio-Dirigida , Natriurese/genética , Natriurese/fisiologia , Oligopeptídeos/antagonistas & inibidores , Oligopeptídeos/metabolismo , Peptidil Dipeptidase A/genética , Domínios Proteicos , Sistema Renina-Angiotensina/fisiologiaRESUMO
Compared with males, females have lower BP before age 60, blunted hypertensive response to angiotensin II, and a leftward shift in pressure natriuresis. This study tested the concept that this female advantage associates with a distinct sexual dimorphic pattern of transporters along the nephron. We applied quantitative immunoblotting to generate profiles of transporters, channels, claudins, and selected regulators in both sexes and assessed the physiologic consequences of the differences. In rats, females excreted a saline load more rapidly than males did. Compared with the proximal tubule of males, the proximal tubule of females had greater phosphorylation of Na+/H+ exchanger isoform 3 (NHE3), distribution of NHE3 at the base of the microvilli, and less abundant expression of Na+/Pi cotransporter 2, claudin-2, and aquaporin 1. These changes associated with less bicarbonate reabsorption and higher lithium clearance in females. The distal nephrons of females had a higher abundance of total and phosphorylated Na+/Cl- cotransporter (NCC), claudin-7, and cleaved forms of epithelial Na+ channel (ENaC) α and γ subunits, which associated with a lower baseline plasma K+ concentration. A K+-rich meal increased the urinary K+ concentration and decreased the level of renal phosphorylated NCC in females. Notably, we observed similar abundance profiles in female versus male C57BL/6 mice. These results define sexual dimorphic phenotypes along the nephron and suggest that lower proximal reabsorption in female rats expedites excretion of a saline load and enhances NCC and ENaC abundance and activation, which may facilitate K+ secretion and set plasma K+ at a lower level.
Assuntos
Eletrólitos/metabolismo , Túbulos Renais/metabolismo , Rim/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Caracteres Sexuais , Animais , Transporte Biológico , Pressão Sanguínea , Feminino , Homeostase , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microvilosidades/metabolismo , Néfrons/metabolismo , Fosforilação , Potássio/metabolismo , Ratos , Ratos Sprague-Dawley , Sódio/metabolismoRESUMO
Augmented intratubular angiotensin (ANG) II is a key determinant of enhanced distal Na+ reabsorption via activation of epithelial Na+ channels (ENaC) and other transporters, which leads to the development of high blood pressure (BP). In ANG II-induced hypertension, there is increased expression of the prorenin receptor (PRR) in the collecting duct (CD), which has been implicated in the stimulation of the sodium transporters and resultant hypertension. The impact of PRR deletion along the nephron on BP regulation and Na+ handling remains controversial. In the present study, we investigate the role of PRR in the regulation of renal function and BP by using a mouse model with specific deletion of PRR in the CD (CDPRR-KO). At basal conditions, CDPRR-KO mice had decreased renal function and lower systolic BP associated with higher fractional Na+ excretion and lower ANG II levels in urine. After 14 days of ANG II infusion (400 ng·kg-1·min-1), the increases in systolic BP and diastolic BP were mitigated in CDPRR-KO mice. CDPRR-KO mice had lower abundance of cleaved αENaC and γENaC, as well as lower ANG II and renin content in urine compared with wild-type mice. In isolated CD from CDPRR-KO mice, patch-clamp studies demonstrated that ANG II-dependent stimulation of ENaC activity was reduced because of fewer active channels and lower open probability. These data indicate that CD PRR contributes to renal function and BP responses during chronic ANG II infusion by enhancing renin activity, increasing ANG II, and activating ENaC in the distal nephron segments.
Assuntos
Angiotensina II , Pressão Sanguínea , Hipertensão/metabolismo , Túbulos Renais Coletores/metabolismo , Natriurese , ATPases Translocadoras de Prótons/deficiência , Receptores de Superfície Celular/deficiência , Eliminação Renal , Sódio/metabolismo , Animais , Modelos Animais de Doenças , Canais Epiteliais de Sódio/metabolismo , Predisposição Genética para Doença , Hipertensão/genética , Hipertensão/fisiopatologia , Hipertensão/prevenção & controle , Túbulos Renais Coletores/fisiopatologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Proteinúria/metabolismo , Proteinúria/fisiopatologia , ATPases Translocadoras de Prótons/genética , Receptores de Superfície Celular/genética , Renina/metabolismo , Cloreto de Sódio na Dieta/administração & dosagem , Cloreto de Sódio na Dieta/metabolismo , Fatores de TempoRESUMO
The World Health Organization ranks hypertension the leading global risk factor for disease, specifically, cardiovascular disease. Blood pressure (BP) is higher in Westernized populations consuming Na+-rich processed foods than in isolated societies consuming K+-rich natural foods. Evidence suggests that lowering dietary Na+ is particularly beneficial in hypertensive individuals who consume a high-Na+ diet. Nonetheless, numerous population studies demonstrate a relationship between higher dietary K+, estimated from urinary excretion or dietary recall, and lower BP, regardless of Na+ intake. Interventional studies with K+ supplementation suggest that it provides a direct benefit; K+ may also be a marker for other beneficial components of a "natural" diet. Recent studies in rodent models indicate mechanisms for the K+ benefit: the distal tubule Na+-Cl- cotransporter (NCC) controls Na+ delivery downstream to the collecting duct, where Na+ reabsorbed by epithelial Na+ channels drives K+ secretion and excretion through K+ channels in the same region. High dietary K+ provokes a decrease in NCC activity to drive more K+ secretion (and Na+ excretion, analogous to the actions of a thiazide diuretic) whether Na+ intake is high or low; low dietary K+ provokes an increase in NCC activity and Na+ retention, also independent of dietary Na+ Together, the findings suggest that public health efforts directed toward increasing consumption of K+-rich natural foods would reduce BP and, thus, cardiovascular and kidney disease.