MMP-2 e MMP-9 na patogênese da lesão neural da hanseníase. / MMP-2 and MMP-9 in the patogenesis of neural injury in leprosy.




Matrix metalloproteinases (MMPs) form a family of zinc-dependent endopeptidases that collectively can degrade all components of the extracellular matrix, influencing process such as migration and cellcell interaction. These enzymes play a crucial role in pathological conditions and tecidual injury including diseases of peripheral nervous system and infectious diseases, principally. Leprosy is characterized by injury of skin and peripheral nerves, this last, a consequence of the interaction of the M. leprae (ML) with the Schwann cells (SC). The production of MMP-2 and MMP-9 is altered in nerve biopsies from leprosy patients suggesting a participation of these proteases in the nerve damage. The purpose of this work was to clarify if SCs are capable to produce MMP-2 and MMP-9 when infected with M.leprae, and if TNF, an important pro inflammatory cytokine in leprosy, is contributing for this production. The human SC line (ST88-14) and primary SC was cultivated and stimulated with ML and TNF by a different time. After that, the total RNA of the cells was extracted and the expression of MMPs and TIMP-1 was evaluated by real time RT-PCR. To verify secretion profile of MMPs and TIMP-1 the cells were culture for 24 hours in the same conditions described before and the supernatants were assayed by ELISA. The same supernatants were submitted to zimography to evaluate the proteolityc activity of MMP-2 and MMP-9. The mRNA expression of MMPs and TIMP-1 was detected constitutively in these cells. However, when the culture was stimulated with ML, MMP- 2 and MMP-9 mRNA levels were increased in relation to control after 6 hour of culture and did not modify TIMP-1 mRNA expression. When MMP-9/TIMP-1 mRNA ratio was analyzed an imbalance in favor to MMP-9 levels was detected in ML-stimulated cells. TNFα in association with ML upregulated MMP-9 mRNA expression and secretion but not MMP-2. The same profile was observed to TIMP-1 but in smallest values suggesting again, an imbalance between MMP-9 and TIMP-1. The activity MMP_9 was not detected in the supernantants when analysed by zimography. In parallel nerve biopsies from leprosy patients was subdivided in four groups: G1 (without histopathological alterations), G2 (nerve with fibrose), G3 (nerve with inflammatory infiltrate and low fibrose) and G4 (nerve with inflammatory infiltrate and higher fibrose). Follow this, the MMPs expression and production was analysed by real time PCR and imunohistochemistry respectively. The MMP-2 mRNA was up-regulate in nerve biopsies of G3 group in contrast with MMP-9 mRNA that was higher in G4 group. TIMP-1 was also higher in biopsies from G4 group but when the ratio between MMP-9 and TIMP-1 was observed the imbalance MMP-9 and the inhibitor was manteined. The imunohistochemistry confirmed the production of MMPs by Schwann cell in vivo in all groups principally in G4 group. These suggesting that both MMPs are up regulated by M.leprae and TNF, probably advents from inflammatory infiltrates and that MMP-9 and TIMP-1 are involved with the fibrose process that occur in the nerve damage of leprosy.


células de schwann leprosy hanseníase metaloproteases trauma do sistema nervoso metalloproteases trauma nervous system mycobacterium leprae imunologia celular schwann cells mycobacterium leprae

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