Antisense inhibition of CD44 tailless splice variant in human articular chondrocytes promotes hyaluronan internalization.
OBJECTIVE
To determine whether alternatively spliced variants of CD44, in particular a short, intracellular tail CD44 isoform, are used by articular chondrocytes to modulate the functions of this matrix receptor.


METHODS
Normal human articular chondrocytes were cultured with or without interleukin-1alpha (IL-1alpha), and the relative expression of CD44 exon 19 and CD44 exon 20, hyaluronan synthase 2, aggrecan, and GAPDH messenger RNA (mRNA) was determined using reverse transcriptase-polymerase chain reaction. Next, CD44 exon 19 mRNA was selectively inhibited by the use of antisense oligonucleotides. The effects of exon 19 loss were analyzed by matrix assembly and hyaluronan internalization assays.


RESULTS
Human articular chondrocytes express varying levels of exon 19 (short tail)- and exon 20 (long tail)-containing CD44 mRNA. Both CD44 mRNA are up-regulated by IL-1alpha. Selective inhibition of CD44 exon 19 results in enhanced hyaluronan internalization and smaller cell-associated matrices.


CONCLUSIONS
The expression of a natural CD44 decoy-like receptor by articular chondrocytes modulates the function of this matrix receptor.
Jiang
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Rush University Graduate School, Chicago, IL, USA.
Knudson
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CB
Knudson
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D053674:Aggrecans; D015153:Blotting, Western; D002358:Cartilage, Articular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D005091:Exons / Q000187:drug effects / Q000235:genetics; D016326:Extracellular Matrix Proteins; D005786:Gene Expression Regulation / Q000187:drug effects; D014453:Glucuronosyltransferase / Q000096:biosynthesis / Q000235:genetics; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D018960:Hyaluronan Receptors / Q000096:biosynthesis / Q000235:genetics*; D000076002:Hyaluronan Synthases; D017403:In Situ Hybridization; D007375:Interleukin-1 / Q000494:pharmacology; D037181:Lectins, C-Type; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D011509:Proteoglycans / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
D053674:Aggrecans; D017931:DNA Primers; D016326:Extracellular Matrix Proteins; D018960:Hyaluronan Receptors; D007375:Interleukin-1; D037181:Lectins, C-Type; D016376:Oligonucleotides, Antisense; D011509:Proteoglycans; D012333:RNA, Messenger; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D014453:Glucuronosyltransferase; C101754:HAS2 protein, human; D000076002:Hyaluronan Synthases