RESUMO
OBJECTIVES: To investigate the role of m.4435A>G and YARS2 c.572G>T (p.G191V) mutations in the development of essential hypertension. METHODS: A hypertensive patient with m.4435A>G and YARS2 p.G191V mutations was identified from previously collected mitochondrial genome and exon sequencing data. Clinical data were collected, and a molecular genetic study was conducted in the proband and his family members. Peripheral venous blood was collected, and immortalized lymphocyte lines constructed. The mitochondrial transfer RNA (tRNA), mitochondrial protein, adenosine triphosphate (ATP), mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) in the constructed lymphocyte cell lines were measured. RESULTS: Mitochondrial genome sequencing showed that all maternal members carried a highly conserved m.4435A>G mutation. The m.4435A>G mutation might affect the secondary structure and folding free energy of mitochondrial tRNA and change its stability, which may influence the anticodon ring structure. Compared with the control group, the cell lines carrying m.4435A>G and YARS2 p.G191V mutations had decreased mitochondrial tRNA homeostasis, mitochondrial protein expression, ATP production and MMP levels, as well as increased ROS levels (all P<0.05). CONCLUSIONS: The YARS2 p.G191V mutation aggravates the changes in mitochondrial translation and mitochondrial function caused by m.4435A>G through affecting the steady-state level of mitochondrial tRNA and further leads to cell dysfunction, indicating that YARS2 p.G191V and m.4435A>G mutations have a synergistic effect in this family and jointly participate in the occurrence and development of essential hypertension.
Assuntos
Hipertensão Essencial , Mutação , RNA de Transferência de Metionina , Tirosina-tRNA Ligase , Feminino , Humanos , Masculino , Hipertensão Essencial/genética , Genoma Mitocondrial , Potencial da Membrana Mitocondrial/genética , Mitocôndrias/genética , Espécies Reativas de Oxigênio/metabolismo , RNA de Transferência/genética , RNA de Transferência de Metionina/genética , Tirosina-tRNA Ligase/genéticaRESUMO
Mannose-binding lectin (MBL), a plasma C-type lectin, plays an important role in innate immunity. However, the interaction, and the consequences of it, between MBL and the immune system remain ill defined. We have investigated the contributing mechanisms and effects of MBL on the proliferation of human monocytes. At lower concentrations (≤4 µg/ml) MBL was shown to partially enhance monocyte proliferation. By contrast, at higher concentrations (8-20 µg/ml) of MBL, cell proliferation was markedly attenuated. MBL-induced growth inhibition was associated with G0/G1 arrest, down-regulation of cyclin D1/D3, cyclin-dependent kinase (Cdk) 2/Cdk4 and up-regulation of the Cdk inhibitory protein Cip1/p21. Additionally, MBL induced apoptosis, and did so through caspase-3 activation and poly ADP-ribose polymerase (PARP) cleavage. Moreover, transforming growth factor (TGF)-ß1 levels increased in the supernatants of MBL-stimulated monocyte cultures. We also found that MBL-dependent inhibition of monocyte proliferation could be reversed by the TGF-ß receptor antagonist SB-431542, or by anti-TGF-ß1 antibody, or by the mitogen-activated protein kinase (MAPK) inhibitors specific for p38 (SB203580), but not ERK (U0126) or JNK (SP600125). Thus, at high concentrations, MBL can affect the immune system by inhibiting monocyte proliferation, which suggests that MBL may exhibit anti-inflammatory effects.
Assuntos
Sistema de Sinalização das MAP Quinases , Lectina de Ligação a Manose/fisiologia , Monócitos/fisiologia , Fator de Crescimento Transformador beta1/fisiologia , Apoptose , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Caspase 3/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Pontos de Checagem da Fase G1 do Ciclo Celular , Regulação da Expressão Gênica , Humanos , Imidazóis/farmacologia , Ligação Proteica , Piridinas/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
OBJECTIVE: To investigate the effects of mannan-binding lectin (MBL) on the functions of human polymorphonuclear cells (PMNs). METHODS: ELISA and Dot blot were performed to examine the binding between MBL and the microorganisms. Flow cytometry and fluorescence microscopy were employed to analyze the phagocytosis of FITC-labeled microorganisms by the PMNs. Real-time quantitative PCR was used to detect the expression levels of IL-1ß, TNF-α and CD11b mRNA in the PMNs, and ELISA used to detect the levels of TNF-α and IL-6 in the supernatants of PMN culture. Nitro-blue tetrazolium reduction assay was used to estimate the levels of superoxide production. RESULTS: MBL bound to the microorganisms in a dose-dependent manner. MBL had no significant effect on phagocytosis of C. albicans and E.coli by the PMNs in the absence of human serum, but in presence of mixed MBL-deficient human sera, MBL promoted the phagocytosis of C. albicans, which could be blocked by mannan. Mannan treatment increased the expressions of IL-1ß, TNF-α, IL-6 and CD11b and enhanced superoxide production in the PMNs. CONCLUSION: MBL can promote phagocytosis of microorganisms by PMNs and increase the expressions of proinflammatory cytokines from PMNs in a complement lectin pathway-dependent manner.
