Hyaluronan and CD44 antagonize mitogen-dependent cyclin D1 expression in mesenchymal cells

Abstract

High molecular weight (HMW) hyaluronan (HA) is widely distributed in the extracellular matrix, but its biological activities remain incompletely understood. We previously reported that HMW-HA binding to CD44 antagonizes mitogen-induced S-phase entry in vascular smooth muscle cells (SMCs; Cuff, C.A., D. Kothapalli, I. Azonobi, S. Chun, Y. Zhang, R. Belkin, C. Yeh, A. Secreto, R.K. Assoian, D.J. Rader, and E. Puré. 2001. J. Clin. Invest. 108:1031–1040); we now characterize the underlying molecular mechanism and document its relevance in vivo. HMW-HA inhibits the mitogen-dependent induction of cyclin D1 and down-regulation of p27kip1 in vascular SMCs. p27kip1 messenger RNA levels were unaffected by HMW-HA, but the expression of Skp2, the rate-limiting component of the SCF complex that degrades p27kip1, was reduced. Rescue experiments identified cyclin D1 as the primary target of HMW-HA. Similar results were observed in fibroblasts, and these antimitogenic effects were not detected in CD44-null cells. Analysis of arteries from wild-type and CD44-null mice showed that the effects of HMW-HA/CD44 on cyclin D1 and Skp2 gene expression are detected in vivo and are associated with altered SMC proliferation after vascular injury.

Hyaluronidase Hyal1 Increases Tumor Cell Proliferation and Motility through Accelerated Vesicle Trafficking

“…Sucrose gradient fractionation confirmed that chloroquine treatment induced a shift in the content of Hyal1WT-tdT (fractions 12-17 in Fig. 4G) to higher density fractions (fractions [13][14][15][16][17][18][19] as well as a small portion localized to the least dense fractions 4 and 6. Moreover, the lower molecular mass band decreased in intensity, consistent with reduced cleavage of Hyal1 as occurs in acidified vesicles.…”

“…The Hyal1 band consistent with the intact secreted mass of Hyal1-tdT is ϳ100 kDa and can be observed to co-fractionate in all three cell lines with EEA1 (fractions 4 -6), cathepsin D (two bands; fractions 13-17), and calnexin (fractions [13][14][15][16][17][18][19], which correspond to fractions of early endosomes, lysosomes, and microsomes (ER), respectively. However, close comparison of the fractions reveals a greater portion of uncleaved enzyme species in the Hyal1E131Q-tdT cell line that specifically extends throughout the denser fractions (fractions 14 -19) of the sucrose gradient in contrast to the wild-type and Y202F mutant, which are more similar to the profile of cathepsin D fractions (fractions [13][14][15][16][17]. These results support an active role in vesicular trafficking by catalytically active Hyal1 cargo.…”

“…Similarly, treatment of breast cancer cells with HA oligomers causes CD44 internalization and prevents efflux of lactate from the cells (16). Conversely, it was shown that high molecular mass HA (Ն1 million Da) inhibited the stimulation of cyclin D1, acting through the CD44 receptor (17).…”

A reciprocal relationship between Rb and Skp2: implications for restriction point control, signal transduction to the cell cycle, and cancer

“…For example, we have shown that the widely expressed ECM component, hyaluronan (HA), acts as a negative regulator of G 1 phase by inhibiting the mitogen-dependent induction of cyclin D1. 12 HA also inhibits mitogen-dependent induction of Skp2 and degradation of p27, but epistasis experiments showed that the effects of HA on Skp2 and p27 are secondary to the inhibition of cyclin D1. 12 Inhibition of the Skp2 autoinduction loop can easily explain how an HA-mediated decrease in cyclin D1 levels would inhibit Skp2 expression and stabilize p27 through inhibition of Rb phosphorylation (Fig.…”

Hyaluronic acid influence on platelet-induced airway smooth muscle cell proliferation

“…CD44, a type 1 transmembrane receptor expressed on the surface of smooth muscle cells and platelets. CD44 exists in many different isoforms that all have HA binding properties [10] and regulate several signaling pathways including Src family kinases, Rho family GTPases, extracellular signal-regulated kinases and mitogen activated protein kinase (MAPK) [11,12] and thereby mediates both cell adhesion and cell growth [13,14].…”