Galectin-3 endocytosis by carbohydrate independent and dependent pathways in different macrophage like cell types

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• 作者：Adriana Lepur^a ; ^{adrianalepur@gmail.com} ; Michael C. Carlsson^a ; Ru膽er Novak^b ; Jerka Dumi膰^b ; Ulf J. Nilsson^c ; Hakon Leffler^a ; ^{hakon.leffler@med.lu.se}
• 关键词：Endocytosis ; Galectin-3 ; M1 macrophages ; M2 macrophages ; THP-1 cell line
• 刊名：Biochimica et Biophysica Acta (BBA)/General Subjects
• 出版年：2012
• 期刊代码：16_03044165
• 类别：bio
• 出版时间：July, 2012
• 卷：1820
• 期：7
• 页码：804-818
• 文件大小：2376 K

摘要

Background

Galectin-3 (the Mac-2 antigen) is abundantly expressed in both macrophage like cells and certain non-macrophage cells. We have studied endocytosis of galectin-3 as one important step relevant for its function, and compared it between variants of a macrophage like cell line, and non-macrophage cells.

Methods

Endocytosis of galectin-3 was observed by fluorescence microscopy and measured by flow cytometry. The endocytosis mechanism was analysed using galectin-3 mutants, galectin-3 inhibitors and endocytic pathways inhibitors in the human leukaemia THP-1 cell line differentiated into na茂ve (M0), classical (M1) or alternatively activated (M2) macrophage like cells, and the non-macrophage cell lines HFL-1 fibroblasts and SKBR3 breast carcinoma.

Results

Galectin-3 endocytosis in non-macrophage cells and M2 cells was blocked by lactose and a potent galectin-3 inhibitor TD139, and also by the R186S mutation in the galectin-3 carbohydrate recognition domain (CRD). In M1 cells galectin-3 endocytosis could be inhibited only by chlorpromazine and by interference with the non-CRD N-terminal part of galectin-3. In all the cell types galectin-3 entered early endosomes within 5-10 min, to be subsequently targeted mainly to non-degradative vesicles, where it remained even after 24 h.

Conclusions

Galectin-3 endocytosis in M1 cells is receptor mediated and carbohydrate independent, while in M2 cells it is CRD mediated, although the non-CRD galectin-3 domain is also involved.

General significance

The demonstration that galectin-3 endocytosis in M1 macrophages is carbohydrate independent and different from M2 macrophages and non-macrophage cells, suggests novel, immunologically significant interactions between phagocytic cells, galectin-3 and its ligands.