Hyaluronan (HA) associates with proteins and proteoglycans to form the extracellular HA-rich matrices that significantly affect cellular behaviors. So far, only the heavy chains of the plasma inter-␣-trypsin inhibitor (ITI) family, designated as SHAPs (serum-derived hyaluronan-associated proteins), have been shown to bind covalently to HA. The physiological significance of such a unique covalent complex has been unknown but is of great interest, because HA and the ITI family are abundant in tissues and in plasma, respectively, and the SHAP-HA complex is formed wherever HA meets plasma. We abolished the formation of the SHAP-HA complex in mice by targeting the gene of bikunin, the light chain of the ITI family members, which is essential for their biosynthesis. As a consequence, the cumulus oophorus, an investing structure unique to the oocyte of higher mammals, had a defect in forming the extracellular HA-rich matrix during expansion. The ovulated oocytes were completely devoid of matrix and were unfertilized, leading to severe female infertility. Intraperitoneal administration of ITI, accompanied by the formation of the SHAP-HA complex, fully rescued the defects. We conclude that the SHAP-HA complex is a major component of the HA-rich matrix of the cumulus oophorus and is essential for fertilization in vivo.

Autografting of fat pads has a long history in plastic and reconstructive surgery for augmentation of lost soft tissue. However, the results are disappointing because of absorption of the grafts with time. The fate of transplanted fat is linked to adipose precursor cells distributed widely in connective tissues. Adipocyte precursor cells can proliferate and mature into adipocytes even in the adult body depending on microenvironment. When reconstituted basement membrane, Matrigel, supplemented with more than 1 ng͞ml bFGF was injected s.c. into 6-week-old mice, the neovascularization induced within 1 week was followed by migration of endogenous adipose precursor cells, and a clearly visible fat pad was formed. The pad grew until 3 weeks after the injection and persisted for at least 10 weeks. Such de novo adipogenesis was induced reproducibly by s.c. injection of Matrigel and bFGF over the chest, lateral abdomen, or head. Adipogenesis could be induced even in ear cartilage or in muscle. Thus, our results demonstrated that an abundant population of adipose precursor cells is distributed widely in connective tissues of the adult body and that they migrate into the neovascularized plug of Matrigel for proliferation and maturation. These results suggest a technique of augmenting lost soft tissue in plastic and reconstructive surgery.

Objective-Therapeutic angiogenesis using autologous stem/progenitor cells represents a novel strategy for severe ischemic diseases. Recent reports indicated that adipose tissues could supply adipose-derived regenerative cells (ADRCs). Accordingly, we examined whether implantation of ADRCs would augment ischemia-induced angiogenesis. Method and Results-Adipose tissue was obtained from C57BL/6J mice, and ADRCs were isolated using standard methods. ADRCs expressed stromal cell-derived factor 1 (SDF-1) mRNA and proteins. Hind limb ischemia was induced and culture-expanded ADRCs, PBS, or mature adipocytes (MAs) as control cells were injected into the ischemic muscles. At 3 weeks, the ADRC group had a greater laser Doppler blood perfusion index and a higher capillary density compared to the controls. Implantation of ADRCs increased circulating endothelial progenitor cells (EPCs). SDF-1 mRNA abundance at ischemic tissues and serum SDF-1 levels were greater in the ADRC group than in the control group. Finally, intraperitoneal injection of an anti-SDF-1 neutralizing antibody reduced the number of circulating EPCs and therapeutic efficacies of ADRCs. hen tissue is exposed to severe ischemia, new blood vessels develop into the ischemic foci to prevent tissue necrosis. Because circulating endothelial progenitor cells (EPCs) have been shown to participate in postnatal neovascularization after mobilization from the bone marrow (BM), 1,2 we have performed basic and clinical studies related to therapeutic angiogenesis using EPCs or BM cells. [3][4][5] We have performed therapeutic angiogenesis using autologous BM mononuclear cell (BM-MNCs) implantation into the ischemic muscles in patients with critical limb ischemia (TACT). 6 -8 Although the safety and efficiency of the TACT protocol have been established, we recently reported that patients with very severe peripheral artery occlusive disease had poor responses to the TACT procedure. 7 Moreover, recent data indicated that patients with severe obstructive vascular disease or multiple coronary risk factors had diminished functions of EPCs and poor responses to angiogenic cell therapy. 9 -12 Thus, alternative source of stem/progenitor cells for therapeutic angiogenesis has been searched extensively. Conclusions-AdiposeRecently, several investigators have reported that adipose tissues contain multipotent mesenchymal stem cells termed adipose-derived regenerative cells (ADRCs), which have an ability to regenerate damaged tissues. [13][14][15] However, little is known as to how implantation of ADRCs would induce angiogenesis in ischemic tissues. It has been known that ADRCs secrete multiple angiogenic growth factors such as vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). 13,14 Such growth factors would mobilize EPCs from the BM into peripheral blood (PB) and finally to ischemic tissues. However, there is limited evidence regarding the effects of in vivo implantation of ADRCs on EPC kinetics during ischemia-induced angiogenesis.Accordingly, we examined ...

Wnt is a family of cysteine-rich secreted glycoproteins, which controls the fate and behavior of the cells in multicellular organisms. In the absence of Drosophila segment polarity gene porcupine (porc), which encodes an endoplasmic reticulum (ER) multispanning transmembrane protein, the N-glycosylation of Wingless (Wg), one of Drosophila Wnt family, is impaired. In contrast, the ectopic expression of porc stimulates the Nglycosylation of both endogenously and exogenously expressed Wg. The N-glycosylation of Wg in the ER occurs posttranslationally, while in the presence of dithiothreitol, it efficiently occurs cotranslationally. Thus, the cotranslational disulfide bond formation of Wg competes with the N-glycosylation by an oligosaccharyl transferase complex. Porc binds the N-terminal 24-amino acid domain (residues 83-106) of Wg, which is highly conserved in the Wnt family and stimulates the N-glycosylation at surrounding sites. Porc is also necessary for the processing of Drosophila Wnt-3/5 in both embryos and cultured cells. Thus, Porc binds the N-terminal specific domain of the Wnt family and stimulates its posttranslational N-glycosylation by anchoring them at the ER membrane possibly through acylation.

The laminin alpha1 chain G domain has multiple biological activities. Previously, we identified cell binding sequences in the laminin alpha1 chain G domain by screening 113 synthetic peptide-polystyrene beads for cell attachment activity. Here, we have used a recombinant protein of the laminin alpha1 G domain (rec-alpha1G) and a large set of synthetic peptides to further identify and characterize heparin, cell, and syndecan-4 binding sites in the laminin alpha1 chain G domain. The rec-alpha1G protein promoted both cell attachment and heparin binding (K(D) = 19 nM). Cell attachment to the rec-alpha1G protein was inhibited 60% by heparin and 30% by EDTA. The heparin binding sites were identified by competing heparin binding to the rec-alpha1G protein with 110 synthetic peptides in solution. Only two peptides, AG73 (IC(50) = 147 microM) and AG75 (IC(50) = 206 microM), inhibited heparin binding to rec-alpha1G. When the peptides were compared in a solid-phase heparin binding assay, AG73 showed more heparin binding than AG75. AG73 also inhibited fibroblast attachment to the rec-alpha1G protein, but AG75 did not. Cell attachment to the peptides was studied using peptide-coated plates and peptide-conjugated sepharose beads. AG73 promoted cell attachment in both assays, but AG75 only showed cell attachment activity in the bead assay. Additionally, AG73, but not AG75, inhibited branching morphogenesis of mouse submandibular glands in organ culture. Furthermore, the rec-alpha1G protein bound syndecan-4, and both AG73 and AG75 inhibited this binding. These results suggest that the AG73 and AG75 sites are important for heparin and syndecan-4 binding in the laminin alpha1 chain G domain. These sites may play a critical role in the diverse biological activities involving heparin and syndecan-4 binding.