Cellular and molecular responses in progressive pseudorheumatoid dysplasia articular cartilage associated with compound heterozygous WISP3 gene mutation

Abstract

Progressive pseudorheumatoid dysplasia (PPD) is characterized by continuous degeneration and loss of articular cartilage, which has been attributed to mutations in the gene encoding WISP3. We collected a PPD family and analyzed their WISP3 genes mutation. Articular chondrocytes (ACs) were purified from the femurs of a PPD patient after hip replacement surgery. Cell growth, proliferation, and viability were examined. Gene expression profiling and analyses of matrix metalloproteinases (MMP)-1, -3, and -13 proteins were carried out using cDNA differential microarrays, real-time reverse transcriptase-polymerase chain reaction (RT-PCR), immunohistochemistry, and Western blot analysis. We found that two probands carried a deletion (840delT) mutation in maternal allele, which leads to truncated WISP3 protein missing 43 residues in C terminus; and a 1000T>C substitution in paternal allele, which was also passed on to four other members in the PPD kindred. PPD ACs were heterogeneous in size with an enhanced rate of cell proliferation and viability compared with the normal ACs. MMP-1, -3, and -13 mRNA expressions were dereased in PPD ACs. MMP-1, -3, and -13 protein levels, however, were increased in cell lysates from PPD ACs, but markedly decreased in the supernatants from cultured ACs. WISP3 mRNA expression in PPD ACs was also decreased. Our results show, for the first time, a compound heterozygous mutation of WISP3 and a series of cellular and molecular changes disturbing the endochondral ossification in this PPD patient.

Delayed-onset of progressive pseudorheumatoid dysplasia in a Chinese adult with a novel compound WISP3 mutation: a case report

“…Subsequently, a total of 18 WISP3 mutations located in exons 2 to 5 have been described in China (Table 1) [2, 7, 8, 11–15]. They include five different mutations (two frameshift mutations and one nonsense mutation) located in exons 2 and 3 (two missense mutations), respectively, as well as five mutations in exon 5 (three frameshift mutations, one nonsense mutation and one missense mutation).…”

“…Zhou et al found that WISP3 was expressed at low levels in articular cartilage chondrocytes in PPD patients [11], a finding that may explain why PPD mainly affects articular cartilage. However, the pathogenic mechanism of the WISP3 gene in PPD remains unclear; thus, a specific therapy is not yet available [3].…”

A genotyping assay for missense mutation in WISP3 gene associated with childhood onset pseudorheumatoid arthropathy

“…WISP3 gene spans over 5 exons and encodes several functional domains each corresponding to one of the exons. Exon 1 encodes a peptide sequence that plays role in Wisp secretion (7,(10)(11)(12); exon 2 codes for insulin-like growth factor binding proteins (IGFBPs) that contains twelve cysteine residues (7,10,12-15); exon 3 encodes a cysteine rich, von Willebrand factor type C repeat domain (10,11,13,15); exon 4 contains information for a thrombospondin type 1 domain biosynthesis (with six cysteine residues) that may bind to sulfated glycosaminoglycan's either at cell surfaces or in extracellular matrix (11,12,(15)(16)(17)(18); and exon 5 that encodes a cysteine knot domain comprised of ten cysteine residues possibly involved in dimerization and receptor binding (10)(11)(12)(14)(15)(16)(17)(19)(20)(21)(22)(23)(24). Until now, a number of mutations and polymorphisms were found throughout the WISP3 sequence with geographically localized origin ( Table 2).…”

“…It was suggested that WISP3 regulates the expression of type II collagen and aggrecan. They are essential cartilage specific molecules which take part in cartilage integrity (22 (21). It implies that protein's WNT inhibitory function requires proper folding of multiple domains.…”

“…It implies that protein's WNT inhibitory function requires proper folding of multiple domains. In case of C78R mutation that corresponds to IGFBP domain, mutant WISP3 is still able to inhibit signaling (7,21).…”