Immobilized Heavy Chain-Hyaluronic Acid Polarizes Lipopolysaccharide-activated Macrophages toward M2 Phenotype

Abstract

Background: HC-HA is a unique anti-inflammatory matrix different from hyaluronic acid (HA). Results: Soluble HC-HA induces apoptosis of inflammatory neutrophils and macrophages, and immobilized HC-HA promotes M2 polarization upon LPS/TLR ligation while both enhancing macrophage phagocytosis. Conclusion: HC-HA exerts its anti-inflammatory action using multiple mechanisms. Significance: HC-HA is the first known matrix component to polarize M2b.Despite the known anti-inflammatory effect of amniotic membrane, its action mechanism remains largely unknown. HC-HA complex (HC-HA) purified from human amniotic membrane consists of high molecular weight hyaluronic acid (HA) covalently linked to the heavy chain (HC) 1 of inter-␣-trypsin inhibitor. In this study, we show that soluble HC-HA also contained pentraxin 3 and induced the apoptosis of both formyl-Met-Leu-Phe or LPS-activated neutrophils and LPS-activated macrophages while not affecting the resting cells. This enhanced apoptosis was caused by the inhibition of cell adhesion, spreading, and proliferation caused by HC-HA binding of LPS-activated macrophages and preventing adhesion to the plastic surface. Preferentially, soluble HC-HA promoted phagocytosis of apoptotic neutrophils in resting macrophages, whereas immobilized HC-HA promoted phagocytosis in LPSactivated macrophages. Upon concomitant LPS stimulation, immobilized HC-HA but not HA polarized macrophages toward the M2 phenotype by down-regulating IRF5 protein and preventing its nuclear localization and by down-regulating IL-12, TNF-␣, and NO synthase 2. Additionally, IL-10, TGF-␤1, peroxisome proliferator-activated receptor ␥, LIGHT (TNF superfamily 14), and sphingosine kinase-1 were up-regulated, and such M2 polarization was dependent on TLR ligation. Collectively, these data suggest that HC-HA is a unique matrix component different from HA and uses multiple mechanisms to suppress M1 while promoting M2 phenotype. This anti-inflammatory action of HC-HA is highly desirable to promote wound healing in diseases heightened by unsuccessful transition from M1 to M2 phenotypes.Inflammation serves as the first host response to real or perceived threats to tissue homeostasis. It is heralded by the recruitment of neutrophils, which eliminate pathogens and damaged tissues before eventually undergoing apoptosis (1-3). These apoptotic neutrophils are then removed by macrophages via phagocytosis, resulting in the restoration and maintenance of anti-inflammatory and tolerogenic milieu (4). On the contrary, delayed neutrophil apoptosis and/or impaired phagocytic clearance of apoptotic neutrophils by macrophages leads to prolonged inflammation that is the hallmark of a number of diseases (5-8). Hence, facilitation of neutrophil apoptosis and phagocytic clearance of apoptotic neutrophils by macrophages is an important strategy to limit inflammation-mediated tissue damage to restore tissue homeostasis (9 -11).Macrophages undergo phenotypic changes to adapt to the transition from proinflammatory to anti-inflammatory states of wou...

Hyaluronan and Its Heavy Chain Modification in Asthma Severity and Experimental Asthma Exacerbation

“…The interaction between HC-HA and CD44 has been observed to promote CD44 "capping" and the digestion of HA by monocytes (32), which could release low molecular weight fragments that have been described as proinflammatory (33). That being said, there is evidence that monocyte incubation with HC-HA induces an anti-inflammatory M2 phenotype (34). This is supported by literature describing an anti-inflammatory role for TSG-6 in different disease models (10,35,36).…”

Exercise reduced pentraxin 3 levels produced by endotoxin-stimulated human peripheral blood mononuclear cells in obese individuals

“…This is particularly worrisome given that our laboratory and others have recently began to elucidate the mechanisms by which PTX3 preferentially increases IL-10 production from isolated PBMCs in normal-weight individuals, down-regulates the proinflammatory signaling cascade, and protects monocytederived macrophages from premature cellular death. 5,15,25,26 These findings have provided evidence to suggest that PTX3 aids in the polarization of monocytederived macrophages from an M1, pro-inflammatory, to an M2, anti-inflammatory phenotype, and thus, important mechanistic targets that may aid in the prevention in obesity-related pro-inflammatory disease, including CVD and T2DM.…”

Low Molecular Weight Hyaluronan Activates Cytosolic Phospholipase A2α and Eicosanoid Production in Monocytes and Macrophages

“…Once the tumor is established and LMW HA is chronically overproduced, it can promote immunosuppressive M2-like tumor-associated macrophage development (104), potentially through PGE 2 and IL-10 signaling as observed in our model. It has also been shown that HA of different sulfation states (106) or covalently linked with the heavy chain 1 of inter-␣-trypsin inhibitor (HC-HA) promotes M2 macrophage polarization (107) and acts in an antiinflammatory manner.…”