TY - JOUR
T1 - Endocytosis of hyaluronidase-1 by the liver
AU - Gasingirwa, M.-C.
AU - Thirion, J.
AU - Mertens-Strijthagen, J.
AU - Wattiaux-De Coninck, S.
AU - Flamion, B.
AU - Wattiaux, R.
AU - Jadot, M.
N1 - MEDLINE® is the source for the MeSH terms of this document.
PY - 2010/9/1
Y1 - 2010/9/1
N2 - It has been suggested that intracellular Hyal-1 (hyaluronidase-1), which is considered a lysosomal enzyme, originates via endocytosis of the serum enzyme. To test this proposal we have investigated the uptake and intracellular distribution of rhHyal-1 (recombinant human Hyal-1) by mouse liver, making use of centrifugation methods. Experiments were performed on wild-type mice injected with I-labelled rhHyal-1 and on Hyal-1 mice injected with the unlabelled enzyme, which were killed at various times after injection. Activity of the unlabelled enzyme was determined by zymography. Intracellular distribution of Hyal-1 was investigated by differential and isopycnic centrifugation. The results of the study indicated that rhHyal-1 is endocytosed by the liver, mainly by sinusoidal cells, and follows the intracellular pathway described for many endocytosed proteins that are eventually located in lysosomes. However, Hyal-1 endocytosis has some particular features. First, endocytosed rhHyal-1 is quickly degraded. Secondly, its distribution, as analysed by differential centrifugation, differs from the distribution of β-galactosidase, taken as the reference lysosomal enzyme. Further analysis by isopycnic centrifugation in a sucrose gradient shows endocytosed rhHyal-1 behaves like β-galactosidase shortly after injection. However the Hyal-1 distribution is markedly less affected than β-galactosidase, following a prior injection of Triton WR-1339, which is a specific density perturbant of lysosomes. The behaviour in centrifugation of endogenous liver Hyal-1, identified by hyaluronan zymography, exhibits some similarity with the behaviour of the endocytosed enzyme, suggesting that it could originate from endocytosis of the serum enzyme. Overall, these results can be explained by supposing that active endocytosed Hyal-1 is mainly present in early lysosomes. Although its degradation half-time is short, Hyal-1 could exert its activity due to a constant supply of active molecules from the blood.
AB - It has been suggested that intracellular Hyal-1 (hyaluronidase-1), which is considered a lysosomal enzyme, originates via endocytosis of the serum enzyme. To test this proposal we have investigated the uptake and intracellular distribution of rhHyal-1 (recombinant human Hyal-1) by mouse liver, making use of centrifugation methods. Experiments were performed on wild-type mice injected with I-labelled rhHyal-1 and on Hyal-1 mice injected with the unlabelled enzyme, which were killed at various times after injection. Activity of the unlabelled enzyme was determined by zymography. Intracellular distribution of Hyal-1 was investigated by differential and isopycnic centrifugation. The results of the study indicated that rhHyal-1 is endocytosed by the liver, mainly by sinusoidal cells, and follows the intracellular pathway described for many endocytosed proteins that are eventually located in lysosomes. However, Hyal-1 endocytosis has some particular features. First, endocytosed rhHyal-1 is quickly degraded. Secondly, its distribution, as analysed by differential centrifugation, differs from the distribution of β-galactosidase, taken as the reference lysosomal enzyme. Further analysis by isopycnic centrifugation in a sucrose gradient shows endocytosed rhHyal-1 behaves like β-galactosidase shortly after injection. However the Hyal-1 distribution is markedly less affected than β-galactosidase, following a prior injection of Triton WR-1339, which is a specific density perturbant of lysosomes. The behaviour in centrifugation of endogenous liver Hyal-1, identified by hyaluronan zymography, exhibits some similarity with the behaviour of the endocytosed enzyme, suggesting that it could originate from endocytosis of the serum enzyme. Overall, these results can be explained by supposing that active endocytosed Hyal-1 is mainly present in early lysosomes. Although its degradation half-time is short, Hyal-1 could exert its activity due to a constant supply of active molecules from the blood.
UR - http://www.scopus.com/inward/record.url?scp=77956664067&partnerID=8YFLogxK
U2 - 10.1042/BJ20100711
DO - 10.1042/BJ20100711
M3 - Article
AN - SCOPUS:77956664067
SN - 0264-6021
VL - 430
SP - 305
EP - 313
JO - Biochemical journal
JF - Biochemical journal
IS - 2
ER -