Role of E-selectin in bleomycin induced lung fibrosis in mice

BACKGROUND

Bleomycin (BLM), a well known anti-cancer drug, often causes acute lung injury and fibrosis by mechanisms that are not well understood. It is suspected that some proteases and active oxygen species generated from inflammatory cells cause the lung injury and subsequent lung fibrosis. It was therefore hypothesised that inhibition of adhesion of inflammatory cells to the endothelium might prevent these developments.

METHODS

BLM (100 mg/kg) was injected into the tail veins of ICR mice to evaluate the induction of E-selectin, an adhesion molecule known to induce neutrophil attachment on endothelial cells. E-selectin mRNA induction was detected by reverse transcriptase polymerase chain reaction (RT-PCR). The myeloperoxidase (MPO) activities in the lung tissues of BLM treated and control mice were compared to evaluate neutrophil infiltration. Pathological changes in the lungs of soluble E-selectin transgenic mice (TG) and their TG negative (non-TG) littermates after BLM treatment were also compared. Serum samples of TG mice and non-TG mice were tested for their ability to block the binding of sialyl Lewis(x) to recombinant E-selectin in vitro.

RESULTS

E-selectin mRNA was maximally induced at six hours after BLM treatment in the ICR mice. The soluble form of E-selectin which can competitively inhibit the binding of sialylated antigens on inflammatory cells to E- and P-selectins on the endothelium was detected in the serum of TG mice. BLM induced lung fibrosis occurred in non-TG mice but not in TG mice. This result confirms the finding that the serum of TG mice inhibits the binding of sialyl Lewis(x) to E-selectin in vitro.

CONCLUSION

E-selectin plays an essential role in BLM induced lung fibrosis through the induction of neutrophil and other inflammatory cell accumulation, and soluble E-selectin may be of use in the prophylactic treatment of lung fibrosis.

Sulfatide and monoclonal antibodies prevent reperfusion injury in skin flaps

Sulfatide binds to P- and L-selectin, which play important roles in the initiation of neutrophil-endothelial interactions. Sulfatide protects skin flaps from ischemia-reperfusion injury. The purpose of this study was to evaluate the augmented protection when anti-rat ICAM-1 and anti-rat LFA-1 antibodies are combined with sulfatide in the ischemia-reperfusion model of rat skin flaps. Sulfatide was administered intravenously just before elevation of the right abdominal epigastric flap, and monoclonal antibodies were injected 30 min before clamp release. The femoral artery and vein were clamped above and below the epigastric vessels for 11 h and then the clamp was released. The administration of both sulfatide and monoclonal antibodies significantly increased the flap surviving area (6.58 +/- 0.61 cm(2) versus the group with monoclonal antibodies alone, 4.43 +/- 0.32 cm(2), P = 0.01). In the untreated rats the area was 1.86 +/- 0.36 cm(2). Histological examination 24 h after reperfusion in the group treated with sulfatide and monoclonal antibodies showed only slight leukocyte invasion into the flap, and myeloperoxidase activity 24 h after reperfusion was significantly reduced. This study indicates that both sulfatide and monoclonal antibodies protect rat skin flaps from ischemia-reperfusion injury.

Constitutive expression of GlyCAM-1 core protein in the rat cochlea

Glycosylation-dependent cell adhesion molecule-1 (GlyCAM-1) is a mucin-like glycoprotein previously identified on high endothelial venules (HEV) of lymph nodes and also in lactating mammary glands. A specifically glycosilated form of GlyCAM-1 on HEV has been shown to be a ligand for a leukocyte L-selectin, which plays an important role in leukocyte rolling along the inflamed endothelium. Here we report that GlyCAM-1 is also expressed in the cochlea. Immunohistochemistry revealed the lateral wall of the cochlea, tectorial membrane, modiolus, organ of corti, and spiral modiolar vein (SMV) to be strongly stained with polyclonal anti-GlyCAM-1 antibody. Moreover, RT-PCR of the cochlear tissue by the use of specific oligonucleotide primers for rat GlyCAM-1 generated a 378 bp product which was then verified by nucleotide sequencing to represent GlyCAM-1. Electron microscopic investigation revealed the presence of GlyCAM-1 over the entire lumenal surface of the vessels, and the basolateral infoldings in stria vascularis. However, soluble L-selectin or mAb MECA-79 which recognizes a carbohydrate epitope on functional L-selectin ligands bound only to the spiral ligament, tectorial membrane and modiolus. These observations suggest that GlyCAM-1 expressed in the cochlear region is heterogenous in terms of its glycosylation.

Significant role of intragraft lymphoid tissues in preventing insulin-dependent diabetes mellitus recurrence in whole pancreaticoduodenal transplantation

Graft recurrence of insulin-dependent diabetes mellitus (IDDM) was examined. Islet transplantation or pancreas-alone transplantation excluding the duodenum and peripancreatic lymph nodes was compared with whole pancreaticoduodenal transplantation. A Wistar Furth (WF; RT1(u), RT6.2) to major histocompatibility complex (MHC)-compatible diabetes-prone (DP; RT1(u), RT6.1 gene carrier)-biobreeding (BB) rat transplantation model was used. Only DP recipients that had been transplanted with whole pancreaticoduodenal grafts were free from IDDM recurrence (>60 days postgrafting) when treated with anti-intercellular adhesion moluecule-1 (ICAM)-1/leukocyte function-associated antigen-1 (LFA-1) monoclonal antibodies (mAbs). In the spleen cells of the DP rats that had accepted pancreatic grafts (60 days postgrafting), flow cytometric analysis showed that NKR-P1(+)TCRalphabeta(+) (NKT) cells had proliferated markedly, with the proportion of 12.8 +/- 1.7% in the total splenic T cells, most of which (86.2%) were derived from the donor (RT6.2(+)). By enzyme-linked immunonosorbent assay (ELISA), serum interferon gamma (IFN-gamma) was not detected (<13 pg/ml) in all rats. However, interleukin-4 (IL-4) was detected as 158.8 +/- 28.0 pg/ml in the nonrecurrent DP recipients. These data suggested that to prevent IDDM recurrence in the pancreatic graft, the lymphocytes in the pancreaticoduodenal grafts are necessary. Also, the donor-derived NKT cells might have some immunoregulatory functions with a Th2 deviation.

An international survey of medical ethics curricula in Asia

SETTING

Medical ethics education has become common, and the integrated ethics curriculum has been recommended in Western countries. It should be questioned whether there is one, universal method of teaching ethics applicable worldwide to medical schools, especially those in non-Western developing countries.

OBJECTIVE

To characterise the medical ethics curricula at Asian medical schools.

DESIGN

Mailed survey of 206 medical schools in China, Hong Kong, Taiwan, Korea, Mongolia, Philippines, Thailand, Malaysia, Singapore, Indonesia, Sri Lanka, Australia and New Zealand.

PARTICIPANTS

A total of 100 medical schools responded, a response rate of 49%, ranging from 23%-100% by country.

MAIN OUTCOME MEASURES

The degree of integration of the ethics programme into the formal medical curriculum was measured by lecture time; whether compulsory or elective; whether separate courses or unit of other courses; number of courses; schedule; total length, and diversity of teachers' specialties.

RESULTS

A total of 89 medical schools (89%) reported offering some courses in which ethical topics were taught. Separate medical ethics courses were mostly offered in all countries, and the structure of vertical integration was divided into four patterns. Most deans reported that physicians' obligations and patients' rights were the most important topics for their students. However, the evaluation was diverse for more concrete topics.

CONCLUSION

Offering formal medical ethics education is a widespread feature of medical curricula throughout the study area. However, the kinds of programmes, especially with regard to integration into clinical teaching, were greatly diverse.

Expression profile of active genes in mouse lymph node high endothelial cells

High endothelial venules (HEV) allow rapid and selective lymphocyte trafficking from the blood into secondary lymphoid tissues. Here we report the expression profile of active genes in mouse high endothelial cells (HEC). HEC were first purified from mouse lymph nodes (LN) by magnetic cell sorting with MECA-79 mAb and a 3'-directed cDNA library that faithfully represents the composition of mRNA was constructed. A total of 1495 cDNA sequences were obtained from randomly selected clones. Based on their sequence identity, they were grouped into 754 different species [gene signatures (GS)] of which 335 GS were identified in GenBank. Among the previously identified genes, expression of several endothelial cell surface molecules including endoglin and ICAM-1 was detected in HEC. Comparison of the gene expression profile with that of purified CD31(+) flat endothelial cells identified several molecules, such as KC chemokine and Duffy antigen/receptor for chemokines, that are known to be selectively expressed in activated endothelial cells or post-capillary venules. Interestingly, mac25/TAF, which is known to be expressed specifically in tumor vessels and implicated in the regulation of cell adhesion, was highly and selectively expressed in HEC in mouse LN, suggesting that it may participate in regulating HEC-specific functions. Comparison with the expression profiles obtained from 35 different cell types showed at least 22 GS that were apparently specific to HEC. Our results illustrate the expression differences between HEC and CD31(+) flat endothelial cells, and will be useful for the identification and characterization of genes specific for HEC.

In vivo effects of monoclonal antibodies against rat beta(2) integrins on kidney ischemia-reperfusion injury

BACKGROUND

Ischemia-reperfusion (IR) involves adhesion of leukocytes to the activated endothelium, leading to tissue damage. CD11/CD18 beta(2) integrins interact with their ligands on endothelial cells and may therefore represent a therapeutic target for the prevention of IR. We investigated the effects of three monoclonal antibodies (mAbs) that recognize epitopes of heavy or light chain of the beta(2) integrins on IR in kidneys.

METHODS

Uninephrectomized Fischer rats were subjected to 45 or 60 min of renal ischemia, treated with intravenously anti-beta(2) integrin monoclonal antibodies (anti-CD11a, anti-CD11b, and anti-CD18) 5 min prior to reperfusion, and compared to a nontreated group. Serum creatinine, blood urea nitrogen (BUN), and kidney histopathological damages were assessed at 1, 2, and 7 days after ischemia.

RESULTS

After 45 and 60 min of ischemia, serum creatinine and BUN were significantly higher in the control than in animals treated with anti-CD11a and anti-CD18 at 24 and 48 h. Administration of anti-CD11b had a beneficial effect on renal function after 45 min but not after 60 min of ischemia. Histologic and immunostaining studies demonstrated mild tubular necrosis and less leukocyte infiltration in the anti-CD11a- and anti-CD18-treated groups compared to the control group.

CONCLUSION

These results indicate that selected antibodies to CD11a/CD18 may decrease kidney IR injury when administered prior to reperfusion.

The effect of flow on the neutrophil-mediated Ca2+ responses in human vascular endothelial cells stimulated by endotoxin

Leukocyte-vascular endothelial cell (EC) interactions which promote inflammatory and immune reactions involve bidirectional signaling between two cell types. We investigated the effects of flow on neutrophil-mediated changes in endothelial intracellular Ca2+ levels ([Ca2+]i). Cultured human umbilical vein ECs stimulated by endotoxin were labeled with Fura-2 and exposed to fluid flow with neutrophils. The individual changes in [Ca2+]i were monitored. The application of flow with neutrophils to stimulated ECs led to an increase in [Ca2+]i although either flow without neutrophils or neutrophils without flow rarely induced a rise in [Ca2+]i. Furthermore, flow application with neutrophils to unstimulated ECs also rarely promoted a rise in [Ca2+]i. These findings suggest that the flow might thus induce or enhance the inflammatory process by the induction of Ca2+ signaling in endotoxin-stimulated endothelium facing neutrophils in the blood flow.

Molecular cloning of mXCR1, the murine SCM-1/lymphotactin receptor

Single C motif-1 (SCM-1)/lymphotactin is a C-type member of the chemokine superfamily. Previously, we identified its specific receptor XCR1. Here we isolated the murine homologue of XCR1 (mXCR1). To demonstrate its biological activity, we produced recombinant mouse SCM-1 by the baculovirus expression system. B300-19 murine pre-B cells expressing mXCR1 responded to mSCM-1 in chemotactic and calcium-mobilization assays. mXCR1 mRNA was weakly expressed in spleen and lung of normal C57BL/6 mice. In spleen, CD8+ cells and NK1.1+ cells were found to express mXCR1. Identification of mXCR1 will now allow us to study the role of this unique cytokine system in the mouse models of inflammation and immunity.

Development of a cell-free binding assay for rat ICAM-1/LFA-1 interactions using a novel anti-rat LFA-1 monoclonal antibody and comparison with a cell-based assay

The importance of the interaction between lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) in the progression of inflammatory responses in vivo has been demonstrated mainly in rats. The present study was undertaken to develop binding assays suitable for measuring the rat ICAM-1/LFA-1 interaction in vitro. We first examined binding of rat T lymphoma FTL43 cells, which express LFA-1, to immobilized rat ICAM-1. Although FTL43 cells bound avidly to immobilized ICAM-1 and the binding was abolished with anti-LFA-1 monoclonal antibodies (mAbs), the binding was not completely inhibited by most anti-ICAM-1 mAbs. We next purified rat LFA-1 from FTL43 cells and constructed a cell-free binding assay. By using a newly developed anti-rat LFA-1 mAb RL14/9, which does not inhibit ICAM-1/LFA-1 interactions, binding of purified rat LFA-1 to immobilized ICAM-1 was successfully detected, whereas only a low signal to noise ratio was observed when binding of ICAM-1 to immobilized LFA-1 was examined. Moreover, we found that simultaneous addition of purified LFA-1 and biotinylated RL14/9 to ICAM-1-coated wells resulted in more sensitive detection of rat ICAM-1/LFA-1 binding. The binding was completely blocked with both anti-LFA-1 and anti-ICAM-1 mAbs and was much more sensitive to inhibition by the ICAM-1-IgG chimera, as compared with the cell-based assay. These results indicate that the cell-free binding assay provides a rapid and sensitive method for screening rat ICAM-1/LFA-1 antagonists, whose therapeutic effect on inflammatory diseases can further be evaluated in vivo.

Requirements for signal delivery through CD44: analysis using CD44-Fas chimeric proteins

CD44 is a transmembrane glycoprotein involved in various cell adhesion events, including lymphocyte migration, early hemopoiesis, and tumor metastasis. To examine the requirements of CD44 for signal delivery through the extracellular domain, we constructed a chimeric CD44 protein fused to the intracellular domain of Fas on its C-terminus. In cells expressing the CD44-Fas fusion protein, apoptosis could be induced by treatment with certain anti-CD44 mAbs alone, especially those recognizing the epitope group d, which has been previously shown to play a role in ligand binding, indicating that ligation of a specific region of the CD44 extracellular domain results in signal delivery. Of note was that appropriate ligation of the epitope h also resulted in the generation of apoptotic signal, although this region was not thought to be involved in ligand binding. In contrast, the so-called blocking anti-CD44 mAbs (epitope group f) that can abrogate the binding of hyaluronate (HA) failed to induce apoptosis even after further cross-linking with the secondary Ab, indicating that a mere mAb-induced oligomerization of the chimeric proteins is insufficient for signal generation. However, these blocking mAbs were instead capable of inhibiting apoptosis induced by nonblocking mAb (epitope group h). Furthermore, a chimeric protein bearing a mutation in the HA binding domain and hence lacking the ability to recognize HA was incapable of mediating the mAb-induced apoptosis, suggesting that the functional integrity of the HA binding domain is crucial to the signal generation in CD44.

High endothelial cells synthesize and degrade sLex. Putative implications for L-selectin-dependent recognition

L-selectin guides lymphocytes into peripheral lymphoid tissues by recognizing glycoprotein ligands decorated with 6-sulfated sialyl Lewis x (sulfo sLex). Here we have used a rat peripheral lymph node high endothelial cell line (Ax) to study in detail the synthesis, expression and degradation of sLex epitope. We show here that Ax cells possess active alpha(1,3)fucosyltransferase Fuc-TVII, the enzyme responsible for the final fucosylation of sialyl-N-acetyllactosamine during sLex synthesis, and express sLex on the cell surface. Furthermore, these cells degrade sLex, primarily by desialylating it to neutral Lex epitopes by alpha(2,3)sialidase(s).

A novel, high endothelial venule-specific sulfotransferase expresses 6-sulfo sialyl Lewis(x), an L-selectin ligand displayed by CD34

L-selectin mediates lymphocyte homing by facilitating lymphocyte adhesion to unique carbohydrate ligands, sulfated sialyl Lewis(x), which are expressed on high endothelial venules (HEV) in secondary lymphoid organs. The nature of the sulfotransferase(s) that contribute to sulfation of such L-selectin counterreceptors has been uncertain. We herein describe a novel L-selectin ligand sulfotransferase, termed LSST, that directs the synthesis of the 6-sulfo sialyl Lewis(x) on L-selectin counterreceptors CD34, GlyCAM-1, and MAdCAM-1. LSST is predominantly expressed in HEV and exhibits striking catalytic preference for core 2-branched mucin-type O-glycans as found in natural L-selectin counterreceptors. LSST enhances L-selectin-mediated adhesion under shear compared to nonsulfated controls. LSST therefore corresponds to an HEV-specific sulfotransferase that contributes to the biosynthesis of L-selectin ligands required for lymphocyte homing.

Retinal ischemia-reperfusion injury attenuated by blocking of adhesion molecules of vascular endothelium

PURPOSE

To evaluate quantitatively the effects of blocking of adhesion molecules (P-selectin or intercellular adhesion molecule-1 [ICAM-1]) on leukocyte dynamics in the retinal microcirculation in vivo during ischemia-reperfusion injury and the therapeutic efficacy of the blocking of adhesion molecules on retinal ischemia-reperfusion injury.

METHODS

Retinal ischemia was induced for 60 minutes in anesthetized pigmented rats by temporary ligation of the optic nerve. P-selectin or ICAM-1 monoclonal antibody (mAb) was administered at 5 minutes before reperfusion. At 4, 12, and 24 hours after onset of reperfusion, leukocyte behavior in the retinal microcirculation was evaluated in vivo with acridine orange digital fluorography. After 7 or 14 days of reperfusion, retinal damage was evaluated histologically.

RESULTS

P-selectin mAb significantly inhibited leukocyte rolling along the major retinal veins after reperfusion. Subsequently, the number of accumulated leukocytes decreased in the P-selectin-inhibited rats. ICAM-1 mAb also inhibited leukocyte accumulation during the reperfusion period in a more substantial manner than P-selectin mAb. Histologic examination demonstrated the protective effect of the blocking of P-selectin or ICAM-1. In accordance with a reduction in leukocyte accumulation, the protective effect of mAb on retinal ischemia-reperfusion injury was more substantial in ICAM-1-inhibited rats.

CONCLUSIONS

The present study demonstrates the inhibitory effect of P-selectin and ICAM-1 mAb on leukocyte accumulation and subsequent tissue injury during retinal ischemia-reperfusion injury.

L-selectin and its ligands mediate infiltration of mononuclear cells into kidney interstitium after ureteric obstruction

It was previously reported that the L-selectin ligands detected by a rat L-selectin and human IgG chimeric molecule (rLEC-IgG) are expressed in the distal tubules of the kidney, where no leukocyte traffic is seen under physiological conditions. In the present study, the role of L-selectin ligands in leukocyte infiltration into the kidney interstitium was investigated using a rat ureteric obstruction model. After ligation of the ureter, ligands for L-selectin rapidly disappeared from tubular epithelial cells and were relocated to the interstitium and peritubular capillary walls, where infiltration of monocytes and CD8(+) T cells subsequently occurred. Mononuclear cell infiltration was significantly inhibited by intravenous injection of a neutralizing monoclonal antibody (MAb) against L-selectin, indicating the possible involvement of an L-selectin-mediated pathway. Interestingly, immunohistochemical studies with a MAb against sulphatide showed that the distribution of sulphatide, known to be one of the candidates of L-selectin ligand, was almost indistinguishable from the staining pattern of rLEC-IgG in both normal and ureteric obstructed kidneys, suggesting that sulphatide and/or related molecule(s) relocated to the renal interstitium were recognized by leukocyte L-selectin, leading to interstitial leukocyte infiltration. In line with this notion, intravenous injection of sulphatide markedly inhibited leukocyte infiltration, suggesting that L-selectin-sulphatide interaction may play a pivotal role in interstitial leukocyte infiltration in the kidney following ureteric obstruction.

Characterization of an apparently conserved epitope in E- and P-selectin identified by dual-specific monoclonal antibodies

E- and P-selectin recognize a wide and overlapping range of oligosaccharide ligands including sialyl-Lewis X (sLeX) through their highly homologous C-type lectin domains. We report that an epitope apparently conserved between E- and P-selectin is functionally involved in ligand recognition although distantly located from the conventional carbohydrate binding site. We found that a previously established anti-E-selectin monoclonal antibody (mAb), 1.2B6, is cross-reactive with P-selectin, and that the 1.2B6 epitope is in the C-type lectin domain and identical to or overlapping with an epitope recognized by other independently established anti-E- and P-selectin dual-specific mAb. The epitope has been mapped by others to a region distant from the previously identified carbohydrate binding site of E-selectin in its three-dimensional structure. Nevertheless, it is of note that all dual-specific mAb, including 1.2B6, inhibited E- or P-selectin-mediated cell adhesion and also binding to sLeX. Engagement of the apparently conserved epitope by the dual-specific mAb may lead to inhibition of the ligand binding ability of E- and P-selectin by a previously uncharacterized mechanism(s) rather than by direct inhibition of sLeX binding to the hitherto identified ligand binding site.

Analysis of the mode of action of a novel immunosuppressant FTY720 in mice

Accelerated lymphocyte homing and apoptosis have been suggested to contribute to potent immunosuppressive effects of FTY720, however, its main mechanism of action remains to be fully elucidated. Here, we examined the mode of action of FTY720 in mice. FTY720, when given at a single dose of 1 mg/kg, markedly decreased the number of peripheral blood lymphocytes (PBL) but moderately increased the lymphocyte numbers in lymph nodes (LN) and Peyer's patches (PP) in normal mice, as previously observed in rats. However, the sharp decrease in PBL numbers was also observed in aly/aly mice lacking LN and PP, indicating that this phenomenon is not explained by accelerated lymphocyte homing to LN and PP. In addition, the finding that a single administration of FTY720 did not suppress proliferative responses of T cells suggested that the PBL reduction could occur without inhibiting lymphocyte functions. However, when administered at the same dose for 2 weeks, FTY720 induced severe systemic lymphopenia, as well as marked suppression of lymphocyte proliferative responses in normal mice. The same treatment also prolonged skin allograft survival in aly/aly mice. Our results suggest that FTY720 suppresses in vivo immune functions mainly by inducing systemic lymphopenia and also by inhibiting T cell functions.

Identification and characterization of ligands for L-selectin in the kidney. III. Characterization of L-selectin reactive heparan sulfate proteoglycans

L-Selectin, a leukocyte adhesion molecule, mediates leukocyte rolling on the endothelium and plays a critical role in leukocyte recruitment at inflammatory sites as well as in lymphocyte homing. We have previously shown that L-selectin reactive chondroitin sulfate and heparan sulfate proteoglycans (HSPGs) are both expressed in the distal tubules of the kidney and that versican is one of the chondroitin sulfate-type ligands. In the present study, we characterized the heparan sulfate-type ligand(s) in more detail. The molecular sizes of HSPGs were approximately 600 kDa with core protein sizes of 160 and 180 kDa. Western blotting analysis showed that L-selectin reactive HSPGs were neither agrin nor perlecan, major basement membrane HSPGs in the kidney. The binding to L-selectin was mediated by the lectin domain of L-selectin in a Ca2+-dependent manner and required heparan sulfate side chains, but not sialic acid. To our knowledge, this is the first biochemical characterization of the L-selectin reactive heparan sulfate proteoglycan(s) in the distal tubules of the kidney.

Identification and characterization of ligands for L-selectin in the kidney. I. Versican, a large chondroitin sulfate proteoglycan, is a ligand for L-selectin

Ligands for a leukocyte adhesion molecule, L-selectin, are expressed not only in the specific vascular endothelium in lymph nodes and Peyer's patches but also in the extravascular tissues such as the brain white matter, choroid plexus and the kidney distal straight tubuli. However, the biological significance of these extravascular ligands is currently unknown. We now report the purification and characterization of a novel extravascular ligand for L-selectin in the kidney using a tubule-derived cell line, ACHN. Binding of L-selectin-IgG chimera (LEC-IgG) to the isolated ligand was specifically blocked with either (i) anti-L-selectin mAb, (ii) EDTA, (iii) fucoidan, (iv) chondroitin sulfate (CS) B or CS E, or (v) treatment with chondroitinases. Partial amino acid sequencing, Western blotting and immunoprecipitation analyses showed that a major ligand for L-selectin in ACHN cells is versican of 1600 kDa. Histochemical as well as biochemical analyses verified that a versican subspecies in the kidney was indeed reactive with L-selectin. Studies with cell lines including those derived from the kidney indicated that a certain glycoform and/or splice form of versican is reactive with L-selectin. Under pathological conditions such as those induced by unilateral ureteral obstruction, versican was shed from the distal straight tubuli and became localized in the adjacent vascular bundles around which a substantial leukocyte infiltration was concomitantly observed. Possible involvement of versican in leukocyte trafficking into the kidney under diseased conditions is discussed.

Identification and characterization of ligands for L-selectin in the kidney. II. Expression of chondroitin sulfate and heparan sulfate proteoglycans reactive with L-selectin

Ligands for the leukocyte adhesion molecule L-selectin are expressed not only in lymph node high endothelial venules (HEV) but also in the renal distal tubuli. Here we report that L-selectin-reactive molecules in the kidney are chondroitin sulfate and heparan sulfate proteoglycans of 500-1000 kDa, unlike those in HEV bearing sialyl Lewis X-like carbohydrates. Binding of L-selectin to these molecules was mediated by the lectin domain of L-selectin and required divalent cations. Binding was inhibited by chondroitinase and/or heparitinase but not sialidase. Thus, L-selectin can recognize chondroitin sulfate and heparan sulfate glycosaminoglycans structurally distinct from sialyl Lewis X-like carbohydrates.