4318

MMP9

CLG4B|GELB|MANDP2|MMP-9;matrix metallopeptidase 9 (gelatinase B, 92kDa gelatinase, 92kDa type IV collagenase);MMP9;matrix metallopeptidase 9 (gelatinase B, 92kDa gelatinase, 92kDa type IV collagenase)

92 kDa gelatinase|92 kDa type IV collagenase|macrophage gelatinase|matrix metalloproteinase 9 (gelatinase B, 92kDa gelatinase, 92kDa type IV collagenase)|matrix metalloproteinase-9|type V collagenase

20q11.2-q13.1

protein-coding

Count: Mmp9; 81687

We hypothesize that pulmonary arterial hypertension (PAH)-associated genes identified by expression profiling of peripheral blood mononuclear cells (PBMCs) from patients with idiopathic pulmonary arterial hypertension (IPAH) can also be identified in PBMCs from scleroderma patients with PAH (PAH-SSc). Gene expression profiles of PBMCs collected from IPAH (n = 9), PAH-SSc (n = 10) patients, and healthy controls (n = 5) were generated using HG_U133A_2.0 GeneChips and were processed by the RMA/GCOS_1.4/SAM_1.21 data analysis pipeline. Disease severity in consecutive patients was assessed by functional status and hemodynamic measurements. The expression profiles were analyzed using PAH severity-stratification, and identified candidate genes were validated with real-time polymerase chain reaction (PCR). Transcriptomics of PBMCs from IPAH patients was highly comparable with that of PMBCs from PAH-SSc patients. The PBMC gene expression patterns significantly correlate with right atrium pressure (RA) and cardiac index (CI), which are known predictors of survival in PAH. Array stratification by RA and CI identified 364 PAH-associated candidate genes. Gene ontology (GO) analysis revealed significant (Z(score) > 1.96) alterations in angiogenesis genes according to PAH severity: matrix metalloproteinase 9 (MMP9) and vascular endothelial growth factor (VEGF) were significantly upregulated in mild as compared with severe PAH and healthy controls, as confirmed by real-time PCR. These data demonstrate that PBMCs from patients with PAH-SSc carry distinct transcriptional expression. Furthermore, our findings suggest an association between angiogenesis-related gene expression and severity of PAH in PAH-SSc patients. Deciphering the role of genes involved in vascular remodeling and PAH development may reveal new treatment targets for this devastating disorder.

OBJECTIVE: To determine the effect of captopril and losartan on the expressions of matrix metalloproteinase-2,9 (MMP-2,9) and metalloproteinase-1 (TIMP-1) in rats with pulmonary arterial hypertension, and the mechanisms of captopril and losartan in intervening the development of pulmonary arterial hypertension. METHODS: Forty male Spraque-Dawley rats were divided into 4 groups randomly: pulmonary arterial hypertension (created by pneumonectomy plus MCT injection) model group (PAH Model), PAH model treated with captopril [PAH+Cap 10 mg/(kg x d)], losartan group [PAH+Los 15 mg/(kg x d)] and normal control group(Control). The mPAP, weight ratio of RV to LV+S, neointima formation, relative thickness of small pulmonary arteries, and degree of muscularization of non-muscular arterioles were measured at day 35. The expression of SM-a-actin in the PASMC was determined by immunochemistry stain. The expressions of MMP-2, 9, TIMP-1 and MMP-2, 9, TIMP-1 mRNA in the pulmonary tissues were determined by immunohistochemistry and FQ-PCR respectively. The enzymatic activity of MMP-2, 9 was measured by Gelatin zymography. RESULTS: Pneumonectomy plus MCT injection induced severe pulmonary arterial hypertension characterized by neointimal formation. Captopril or losartan suppressed the increase of mPAP, right ventricle weight, thickness of small pulmonary arteries and muscularization of peripheral pulmonary arterioles in the rats with PAH (P < 0.05). The PAH model group had higher expressions of MMP-2, 9, TIMP-1 mRNA and enzymatic activity of MMP-2, 9 in lung tissue than the other groups (P < 0.05). Captopril intervention had similar effects as losartan intervention. CONCLUSION: The captopril and losartan induced attenuation of PAH and pulmonary vascular remodeling is likely to be associated with the regulation of the expressions of MMP-2, 9, TIMP-1.

Current data suggest that Toll-like receptor 4 (TLR4), a key molecule in the innate immune response, may also be activated following tissue injury. Activation of this receptor is known to induce the production of several proinflammatory cytokines. Given that pulmonary inflammation has been shown to be a key contributor to chronic hypoxia-induced pulmonary vascular remodeling, the authors hypothesized that TLR4-deficient mice would be less susceptible to pulmonary hypertension (PH) as compared to mice with intact TLR4. TLR4-deficient and TLR4-intact strains of inbred mice were exposed to 4, 8, and 16 weeks of hypoxia (0.10 FiO(2)) or normoxia (0.21 FiO(2)) in a normobaric chamber. After chronic hypoxic exposure, TLR4-intact mice developed significant PH evidenced by increased right ventricular systolic pressure, right ventricular hypertrophy, and pulmonary artery medial thickening. In contrast, TLR4-deficient mice had no significant change in any of these parameters and this was associated with decreased pulmonary vascular inflammatory response as compared to the TLR4-intact mice. These results suggest that TLR4 deficiency may decrease the susceptibility to developing PH by attenuating the pulmonary vascular inflammatory response to chronic hypoxia.