Arylsulfatase B regulates versican expression by galectin-3 and AP-1 mediated transcriptional effects

Abstract

Arylsulfatase B (N-acetylgalactosamine-4-sulfatase; ARSB) removes 4-sulfate groups from chondroitin-4-sulfate (C4S) and dermatan sulfate and is required for their degradation. In human prostate stromal and epithelial cells, when ARSB was silenced, C4S, versican, and versican promoter activity increased, and the galectin-3 that co-immunoprecipitated with C4S declined. Galectin-3 silencing inhibited the ARSB-silencing induced increases in versican and versican promoter, due to effects on the AP-1 binding site in the versican promoter. These findings demonstrate for the first time the transcriptional mechanism whereby ARSB can regulate expression of an extracellular matrix proteoglycan with C4S attachments. In addition, following ARSB silencing, C4S that co-immunoprecipitated with versican increased, whereas co-immunoprecipitated EGFR declined, total EGFR increased, and exogenous EGF-induced cell proliferation increased, suggesting profound effects of ARSB on vital cell processes.

Increased Expression of Colonic Wnt9A through Sp1-mediated Transcriptional Effects involving Arylsulfatase B, Chondroitin 4-Sulfate, and Galectin-3

“…This finding is consistent with the reported decline in binding of galectin-3, -7, and -9 to more highly sulfated chondroitin, which was observed by frontal affinity chromatography (23). Coincident with reduced binding of galectin-3 to C4S, we have shown increases in nuclear galectin-3, which enabled transcriptional events mediated by AP-1, including increased expression of HIF-1␣ and versican, in human bronchial, colonic, and prostate cells (21,22). Galectin-3 interacts with heterogeneous ribonucleoprotein and may contribute to malignant transformation in various epithelial tissues, including human colonic cells (21, 24 -26).…”

“…Heterozygous arylsulfatase B-deficient mice were obtained (strain 005598; The Jackson Laboratory) and bred (22,35). Genotyping was performed to detect the mutation in ARSB (NM_009712.3), a G-to-T mutation at residue 94,560,057 (University of California, Santa Cruz database) in exon 2, leading to truncation and reduced activity.…”

“…siRNA sequences for ARSB (NM_000046) silencing were as follows: sense, 5Ј-GGGUAUGGUCUCUAGGCA-3Ј; antisense, 5Ј-UUGCC-UAGAGACCAUACCC-3Ј. The sequence of the DNA template for human galectin-3 silencing (Hs_LGALS3_9) was 5Ј-ATG-ATGTTGCCTTCCACTTTA-3Ј (22). For Sp1 siRNA, the DNA target sequence was 5Ј-TTGGGTAAGTGTGTTGTT-TAA-3Ј.…”

“…Chromatin Immunoprecipitation Assay for Sp1 and Galectin-3-Binding of Sp1 and galectin-3 to the Wnt9A promoter was assessed by chromatin immunoprecipitation (ChIP) assay (22). For ChIP, IgG control, control silenced, ARSB-silenced, carrageenan-treated, carrageenan-exposed, and galectin-3 silenced, and ARSB-and galectin-3-silenced colonic epithelial cells were fixed with 1% formaldehyde for 10 min at room temperature.…”

“…In our previous work, we have reported a novel transcriptional mechanism, whereby decline in ARSB can lead to increased transcription of HIF-1␣ and of versican, due to reduced binding of galectin-3 with chondroitin 4-sulfate when chondroitin 4-sulfate (C4S) 2 is more highly sulfated following decline in ARSB activity (21,22). This finding is consistent with the reported decline in binding of galectin-3, -7, and -9 to more highly sulfated chondroitin, which was observed by frontal affinity chromatography (23).…”