Cleavage of Osteopontin by Matrix Metalloproteinase-12 Modulates Experimental Autoimmune Encephalomyelitis Disease in C57BL/6 Mice

Abstract

A role for osteopontin (OPN) in promoting disease activity of multiple sclerosis or its animal model experimental autoimmune encephalomyelitis (EAE) has recently been suggested. As the biological activity of OPN is heavily influenced by posttranslational processing, we investigated the capacity of matrix metalloproteinase (MMP)-12 to cleave OPN and determined whether this influenced disease activity. We found that OPN mRNA and protein expression in the spinal cord increased with EAE disease in C57BL/6 mice concurrently with MMP-12 expression. A Western blot of EAE and control spinal cords revealed different OPNimmunoreactive bands, with a pattern that was similar to MMP-12 cleavage of recombinant OPN in vitro. In addition, OPN fragments in the spinal cord of EAEafflicted mice were reduced in MMP-12 ؊/؊ mice compared with wild-type controls. However, examination of OPN ؊/؊ mice in short-and long-term experiments revealed no difference in EAE outcomes from wildtype animals. OPN/MMP-12 double null mice were generated, and it was revealed that MMP-12 ؊/؊ mice had a worsening of disease compared with wild-type mice, which returned to wild-type levels in the OPN/ MMP-12 double null mice. These results suggest that EAE disease activity may be modulated by the cleavage of OPN by

Initial Pulmonary Respiration Causes Massive Diaphragm Damage and Hyper-CKemia in Duchenne Muscular Dystrophy Dog

“…Western blotting showed a main band of osteopontin at 69 kDa in both normal and dystrophic dogs before and after the respiration (Figure 3B and 3C). The main band sizes were roughly comparable to data in other reports1112. The 69 kDa osteopontin level before and after the respiration in dystrophic dogs was significantly increased compared to that in normal dogs, although the difference was not outstanding compared to mRNA levels (Figure 3D).…”

Osteopontin Bridging Innate and Adaptive Immunity in Autoimmune Diseases

“…In line with this view, MMP-12-deficient mice develop more severe EAE than wild type mice, and this effect disappears in OPN/MMP-12 double-deficient mice [46, 47]. …”

“…Human OPN contains three cleavage sites for MMPs located between the amino acids Gly 166 -Leu 167 , Ala 201 -Tyr 202 , and Asp 210 -Leu 211 . Interestingly, MMP-12 processes OPN into a less-inflammatory form, or, alternatively, it generates OPN peptides with anti-inflammatory properties [47]. …”

Osteopontin and multiple sclerosis: An update

“…In contrast to these findings, other studies have found no altered susceptibility of OPN-deficient mice to EAE compared with wild-type mice. 46,47 Although the reasons for this discrepancy are unclear, it could reflect the particular nature of the genetic OPN deletion involved. 47 The administration of recombinant OPN triggers recurrent relapses, promotes the worsening of paralysis and induces neurological defects, including optic neuritis.…”

“…46,47 Although the reasons for this discrepancy are unclear, it could reflect the particular nature of the genetic OPN deletion involved. 47 The administration of recombinant OPN triggers recurrent relapses, promotes the worsening of paralysis and induces neurological defects, including optic neuritis. 42 One of the mechanisms underlying the effects of recombinant OPN is the promotion of activated T cell survival by enhanced inhibition and activation of transcription factors, as well as the altered expression of proapoptotic proteins.…”