Specific Sizes of Hyaluronan Oligosaccharides Stimulate Fibroblast Migration and Excisional Wound Repair

Abstract

The extracellular matrix polysaccharide hyaluronan (HA) plays a key role in both fibrotic and regenerative tissue repair. Accumulation of high molecular weight HA is typical of regenerative repair, which is associated with minimal inflammation and fibrosis, while fragmentation of HA is typical of postnatal wounds, which heal in the presence of inflammation and transient fibrosis. It is generally considered that HA oligosaccharides and fragments of a wide size range support these processes of adult, fibrotic wound repair yet the consequences of sized HA fragments/oligosaccharides to each repair stage is not well characterized. Here, we compared the effects of native HA, HA oligosaccharide mixtures and individual sizes (4–10mer oligosaccharides, 5 and, 40 kDa) of HA oligosaccharides and fragments, on fibroblast migration in scratch wound assays and on excisional skin wound repair in vivo. We confirm that 4–10mer mixtures significantly stimulated scratch wound repair and further report that only the 6 and 8mer oligosaccharides in this mixture are responsible for this effect. The HA 6mer promoted wound closure, accumulation of wound M1 and M2 macrophages and the M2 cytokine TGFβ1, but did not increase myofibroblast differentiation. The effect of 6mer HA on wound closure required both RHAMM and CD44 expression. In contrast, The 40 kDa HA fragment inhibited wound closure, increased the number of wound macrophages but had no effect on TGFβ1 accumulation or subsequent fibrosis. These results show that specific sizes of HA polymer have unique effects on postnatal wound repair. The ability of 6mer HA to promote wound closure and inflammation resolution without increased myofibroblast differentiation suggests that this HA oligosaccharide could be useful for treatment of delayed or inefficient wound repair where minimal fibrosis is advantageous.

Extracellular Matrix and Dermal Fibroblast Function in the Healing Wound

“…103,104 Adding interest, if not a little confusion, it has further been shown that specific very small-sized hexameric HA fragments (*1 kDa) improve fibroblast migration and promote wound closure, while decreasing myofibroblast differentiation and fibrosis. 105 These data suggest that hexameric HA might be of interest in the healing of chronic wounds.…”

Hyaluronan as a therapeutic target in human diseases

“…Abnormal accumulation of HA matrix promotes fibroblast cell migration [11]. Specific sizes of HA oligosaccharides stimulate fibroblast migration and excisional wound repair [147]. Both CD44 [148] and HMMR [57] have been shown to have a role in fibroblast migration during tissue injury.…”

Biology and biotechnology of hyaluronan

“…Ultimately, even in lung inflammation and several lung diseases, including asthma and pneumonia, has been described an increased production of HA [90,91]. Interestingly, tumor necrosis factor-stimulated gene-6 (TSG-6) amplifies HA synthesis by airway smooth muscle cells in lung inflammation and stabilizes the HA polymer structure catalyzing the transfer of chondroitin sulphate chains from bikunin to HA chains [91,92,120].…”

“…In all of these processes, HA plays a pivotal role and altered HA content affects wound healing altering a normal scar formation [92]. The role of HA content in microenvironment is therefore critical and considering that in most cancers it has been described an inflammatory microenvironment, it is not surprisingly that HA is present in most of the solid tumours [21,93].…”