Inhibition of Notch4 using Novel Neutralizing Antibodies Reduces Tumor Growth in Murine Cancer Models by Targeting the Tumor Endothelium.

Endothelial Notch signaling is critical for tumor angiogenesis. Notch1 blockade can interfere with tumor vessel function but causes tissue hypoxia and gastrointestinal toxicity. Notch4 is primarily expressed in endothelial cells, where it may promote angiogenesis; however, effective therapeutic targeting of Notch4 has not been successful. We developed highly specific Notch4-blocking antibodies, 6-3-A6 and humanized E7011, allowing therapeutic targeting of Notch4 to be assessed in tumor models. Notch4 was expressed on tumor endothelial cells in multiple cancer models, and endothelial expression was associated with response to E7011/6-3-A6. Anti-Notch4 treatment significantly delayed tumor growth in mouse models of breast, skin, and lung cancer. Enhanced tumor inhibition occurred when anti-Notch4 treatment was used in combination with chemotherapeutics. Endothelial transcriptomic analysis of murine breast tumors treated with 6-3-A6 identified significant changes in pathways of vascular function but caused only modest change in canonical Notch signaling. Analysis of early and late treatment timepoints revealed significant differences in vessel area and perfusion in response to anti-Notch4 treatment. We conclude that targeting Notch4 improves tumor growth control through endothelial intrinsic mechanisms.

Association of Gut Microbial Genera with Heart Rate Variability in the General Japanese Population: The Iwaki Cross-Sectional Research Study.

The gut microbiota has become a significant factor associated with health and disease. Although many studies have reported the implications of changes in the gut microbiota on cardiovascular diseases, there are no reports on the relationship between heart rate variability (HRV) and the gut microbiota. Therefore, we investigated the association between gut microbiota abundance and HRV parameters in this cross-sectional study of the general Japanese population. This study included 950 participants of the Iwaki Health Promotion Project who underwent a medical examination in 2019 that included HRV and gut microbiota measurements. At the genus level, multivariate regression analysis showed that higher gut microbial diversity was associated with a higher standard deviation of RR intervals (SDNN). Moreover, a higher SDNN was associated with a higher relative count of Lachnospiraceae incertae sedis. L. incertae sedis abundance was associated with higher HRV parameters such as SDNN, coefficient of variation of RR intervals, low-frequency component power (LF)/high-frequency component power, and LF. In the general Japanese population, higher gut microbial diversity and L. incertae sedis abundance were associated with higher HRV parameters.

Correlation between Glycation-Related Biomarkers and Quality of Life in the General Japanese Population: The Iwaki Cross-Sectional Research Study.

The correlation between diabetes-related biomarkers and quality of life (QOL) remains unclear. In this cross-sectional study, we investigated the correlation between diabetes-related biomarkers and QOL in a general Japanese population who underwent health checkups as a part of the Iwaki Health Promotion Project. Male and female participants aged ≥ 20 years from Iwaki District, Hirosaki City, Aomori Prefecture who participated in the 2019 medical evaluation were recruited. QOL was evaluated using the Short Form Health Survey 36 (SF-36). Fasting blood glucose, homeostatic model assessment-estimated insulin resistance (HOMA-IR), hemoglobin A1c (HbA1c), glycoalbumin, and plasma pentosidine were also evaluated as diabetes-related markers. Of the 1065 recruited participants, 1053 completed the clinical and QOL evaluations. Multivariate regression analysis revealed that upregulated diabetes-related markers levels were correlated with decreased SF-36 scores. Blood glucose, HOMA-IR, HbA1c, glycoalbumin, and plasma pentosidine levels were correlated with general health. Moreover, plasma pentosidine levels were correlated with role physical, social functioning, and role emotional in addition to general health. These results indicated that the levels of diabetes-related biomarkers, particularly the levels of plasma pentosidine, a glycation marker, were associated with QOL in our cohort.

Factors Associated with Reduced Heart Rate Variability in the General Japanese Population: The Iwaki Cross-Sectional Research Study.

Although many studies have reported factors associated with reduced heart rate variability (HRV) in Western populations, evidence is limited among Asian populations. Therefore, we investigated the factors associated with reduced HRV values in a general Japanese population by measuring HRV among the participants of the Iwaki Health Promotion Project who underwent medical examination in 2019. We performed 90-s HRV measurements in 1065 participants. Of these, we evaluated the coefficient of variation in R-R intervals (CVRR) and standard deviation in R-R intervals (SDNN). Blood was collected under a fasting condition, and investigations of glucose metabolism, lipid metabolism, renal function, liver function, advanced glycation end products, and blood pressure were performed. A multivariate regression analysis of the association between CVRR or SDNN and blood test parameters and blood pressure in 987 participants with adequately completed HRV assessments showed that reduced CVRR or SDNN was associated with higher levels of glycated hemoglobin (HbA1c), glycoalbumin, blood glucose, triglycerides, creatinine, plasma pentosidine, and diastolic blood pressure. In the general Japanese population, higher levels of HbA1c, glycoalbumin, blood glucose, triglycerides, creatinine, plasma pentosidine, and diastolic blood pressure are associated with reduced CVRR or SDNN, which are typical HRV parameters.

Resolution of fibrosis by siRNA HSP47 in vitamin A-coupled liposomes induces regeneration of chronically injured livers.

BACKGROUND AND AIM: In chronic hepatic diseases where treatment strategies are not available, deposited fibrotic tissues deteriorate the intrinsic regeneration capacity of the liver by creating special restrictions. Thus, if the anti-fibrosis modality is efficiently applied, the regeneration capacity of the liver should be reactivated even in such refractory hepatic diseases. METHODS: Rat liver fibrosis was induced by dimethyl-nitrosamine (DMN). Another liver fibrosis model was established in CCl4 treated Sox9CreERT2ROSA26: YFP mice. To resolve hepatic fibrosis, vitamin A-coupled liposomes containing siRNA HSP47 (VA-liposome siHSP47) were employed. EpCAM + hepatic progenitor cells from GFP rats were transplanted to DMN rat liver to examine their trans-differentiation into hepatic cells after resolution of liver fibrosis. RESULTS: Even under continuous exposure to such strong hepatotoxin as DMN, rats undergoing VA-liposome siHSP47 treatment showed an increment of DNA synthesis of hepatocytes with the concomitant restoration of impaired liver weight and normalization of albumin levels. These results were consistent with the observation that GFP + EpCAM hepatic progenitor cells transplanted to DMN rat liver, trans-differentiated into GFP + mature hepatic cells after VA-liposome siHSP47 treatment. Another rodent model also proved regeneration potential of the fibrotic liver in CCl4 administered Sox9CreERT2ROSA26: YFP mice, VA-liposome siHSP47 treatment-induced restoration of liver weight and trans-differentiation of YEP + Sox9 + cells into YFP + hepatic cells, although because of relatively mild hepatotoxicity of CCl4, undamaged hepatocytes also proliferated. CONCLUSIONS: These results demonstrated that regeneration of chronically damaged liver indeed occurs after anti-fibrosis treatment even under continuous exposure to hepatotoxin, which promises a significant benefit of the anti-fibrosis therapy for refractory liver diseases.

Blockade of the fractalkine-CX3CR1 axis ameliorates experimental colitis by dislodging venous crawling monocytes.

Chemokine systems modulate inflammatory and immune responses in inflammatory bowel disease (IBD). The colons of IBD patients show increased levels of fractalkine (FKN) and high numbers of FKN receptor-positive (CX3CR1+) cells; however, the FKN-CX3CR1 axis's role in intestinal inflammation, especially in intravascular leukocyte behaviors, still remains unclear. Here, we show that interruption of the FKN-CX3CR1 axis by anti-FKN monoclonal antibody (mAb) ameliorates murine colitis through regulation of intravascular monocyte behaviors in murine colitis models. FKN expression was detectable in vascular endothelium and CX3CR1+ macrophages accumulated in the mucosal lamina propria and submucosa of the inflamed colons. CD115+ monocytes tethered to the venous endothelium and expressed pro-inflammatory mediators. The anti-FKN mAb improved colitis symptoms, markedly reduced pro-inflammatory factors in the colon, maintained blood vessel integrity and reduced tethered monocytes in the inflamed veins. Intravital imaging revealed that CD115+Gr-1low/- monocytes crawled on the apical surfaces of venous endothelium, and anti-FKN mAb rapidly dislodged the crawling monocytes and inhibited their patrolling behavior. These findings suggest that the FKN-CX3CR1 axis triggers the patrolling behavior of crawling monocytes on the venous endothelium of inflamed colons, and accelerates the subsequent leukocyte activation and infiltration by locally producing inflammatory cytokines and chemokines. The mAb also ameliorated symptoms in another IBD model, T-cell-transferred colitis. Blocking the FKN-CX3CR1 axis with an anti-FKN mAb considerably inhibits the colitis-triggered inflammatory cascades, which may be an alternative strategy to treat IBD.

Role of Anti-Fractalkine Antibody in Suppression of Joint Destruction by Inhibiting Migration of Osteoclast Precursors to the Synovium in Experimental Arthritis.

OBJECTIVE: To elucidate the role of the fractalkine (FKN)/CX3 CR1 pathway in joint destruction in rheumatoid arthritis. METHODS: We examined the effect of treatment with anti-mouse FKN (anti-mFKN) monoclonal antibody (mAb) on joint destruction and the migration of osteoclast precursors (OCPs) into the joint, using the collagen-induced arthritis (CIA) model. DBA/1 mice were immunized with bovine type II collagen to induce arthritis, and then treated with anti-mFKN mAb. Disease severity was monitored by arthritis score, and joint destruction was evaluated by soft x-ray and histologic analyses. Plasma levels of joint destruction markers were assessed by enzyme-linked immunosorbent assay. FKN expression on endothelial cells was detected by immunohistochemistry. Bone marrow-derived OCPs were labeled with fluorescein and transferred to mice with CIA, and the migration of the OCPs to the joints was then analyzed. RESULTS: Both prophylactic and therapeutic treatment with anti-mFKN mAb significantly decreased the arthritis and soft x-ray scores. Plasma levels of cartilage oligomeric matrix protein and matrix metalloproteinase 3 decreased after treatment with anti-mFKN mAb. Histologic analysis revealed that anti-mFKN mAb inhibited synovitis, pannus formation, and cartilage destruction, as well as suppressed bone damage, with a marked reduction in the number of tartrate-resistant acid phosphatase-positive osteoclasts. Anti-mFKN mAb strongly inhibited the migration of bone marrow-derived OCPs into the affected synovium. CONCLUSION: Anti-mFKN mAb notably ameliorates arthritis and joint destruction in the CIA model, as well as inhibits migration of OCPs into the synovium. These results suggest that inhibition of the FKN/CX3 CR1 pathway could be a novel strategy for treatment of both synovitis and joint destruction in rheumatoid arthritis.

Involvement of Pancreatic Stellate Cells in Regeneration of Remnant Pancreas after Partial Pancreatectomy.

BACKGROUND AND OBJECTIVES: Mechanism of regeneration of remnant pancreas after partial pancreatectomy (PX) is still unknown. In this study, effect of siRNA against the collagen specific chaperone, HSP47, which inhibits collagen secretion from activated pancreas stellate cells (aPSCs), and induces their apoptosis, on regeneration of remnant pancreas was determined. METHODS: Pancreatectomy was performed according to established methods. Proliferation of cells was assessed by BrdU incorporation. Immunostaining of HSP47 was employed to identify PSCs. Progenitor cells were identified by SOX9 staining. Acinar cells were immunostained for amylase. Co-culture of acinar cells with aPSCs were carried out in a double chamber with a cell culture insert. siRNA HSP47 encapsulated in vitamin A-coupled liposome (VA-lip siRNA HSP47) was delivered to aPSCs by iv injection. RESULTS: In remnant pancreas of 90% PX rat, new areas of foci were located separately from duodenal areas with normal pancreatic features. After PX, BrdU uptake of acinar cells and islet cells significantly increased, but was suppressed by treatment with VA-lip siRNA HSP47. BrdU uptake by acinar cells was augmented by co-culturing with aPSCs and the augmentation was nullified by siRNA HSP47. BrdU uptake by progenitor cells in foci area was slightly enhanced by the same treatment. New area which exhibited intermediate features between those of duodenal and area of foci, emerged after the treatment. CONCLUSION: aPSCs play a crucial role in regeneration of remnant pancreas, proliferation of acinar and islet cells after PX through the activity of secreted collagen. Characterization of new area emerged by siRNA HSP47 treatment as to its origin is a future task.

High affinity IgM(+) memory B cells are generated through a germinal center-dependent pathway.

During a T cell-dependent immune response, B cells undergo clonal expansion and selection and the induction of isotype switching and somatic hypermutation (SHM). Although somatically mutated IgM(+) memory B cells have been reported, it has not been established whether they are really high affinity B cells. We tracked (4-hydroxy-3-nitrophenyl) acetyl hapten-specific GC B cells from normal immunized mice based on affinity of their B cell receptor (BCR) and performed BCR sequence analysis. SHM was evident by day 7 postimmunization and increased with time, such that high affinity IgM(+) as well as IgG(+) memory B cells continued to be generated up to day 42. In contrast, class-switch recombination (CSR) was almost completed by day 7 and then the ratio of IgG1(+)/IgM(+) GC B cells remained unchanged. Together these findings suggest that IgM(+) B cells undergo SHM in the GC to generate high affinity IgM(+) memory cells and that this process continues even after CSR is accomplished.

Generation of a Tlx1(CreER-Venus) knock-in mouse strain for the study of spleen development.

The spleen is a lymphoid organ that serves as a unique niche for immune reactions, extramedullary hematopoiesis, and the removal of aged erythrocytes from the circulation. While much is known about the immunological functions of the spleen, the mechanisms governing the development and organization of its stromal microenvironment remain poorly understood. Here we report the generation and analysis of a Tlx1(Cre) (ER) (-Venus) knock-in mouse strain engineered to simultaneously express tamoxifen-inducible CreER(T2) and Venus fluorescent protein under the control of regulatory elements of the Tlx1 gene, which encodes a transcription factor essential for spleen development. We demonstrated that Venus as well as CreER expression recapitulates endogenous Tlx1 transcription within the spleen microenvironment. When Tlx1(Cre) (ER) (-Venus) mice were crossed with the Cre-inducible reporter strain, Tlx1-expressing cells as well as their descendants were specifically labeled following tamoxifen administration. We also showed by cell lineage tracing that asplenia caused by Tlx1 deficiency is attributable to altered contribution of mesenchymal cells in the spleen anlage to the pancreatic mesenchyme. Thus, Tlx1(Cre) (ER) (-Venus) mice represent a new tool for lineage tracing and conditional gene manipulation of spleen mesenchymal cells, essential approaches for understanding the molecular mechanisms of spleen development.

Activated hepatic stellate cells are dependent on self-collagen, cleaved by membrane type 1 matrix metalloproteinase for their growth.

Stellate cells are distributed throughout organs, where, upon chronic damage, they become activated and proliferate to secrete collagen, which results in organ fibrosis. An intriguing property of hepatic stellate cells (HSCs) is that they undergo apoptosis when collagen is resolved by stopping tissue damage or by treatment, even though the mechanisms are unknown. Here we disclose the fact that HSCs, normal diploid cells, acquired dependence on collagen for their growth during the transition from quiescent to active states. The intramolecular RGD motifs of collagen were exposed by cleavage with their own membrane type 1 matrix metalloproteinase (MT1-MMP). The following evidence supports this conclusion. When rat activated HSCs (aHSCs) were transduced with siRNA against the collagen-specific chaperone gp46 to inhibit collagen secretion, the cells underwent autophagy followed by apoptosis. Concomitantly, the growth of aHSCs was suppressed, whereas that of quiescent HSCs was not. These in vitro results are compatible with the in vivo observation that apoptosis of aHSCs was induced in cirrhotic livers of rats treated with siRNAgp46. siRNA against MT1-MMP and addition of tissue inhibitor of metalloproteinase 2 (TIMP-2), which mainly inhibits MT1-MMP, also significantly suppressed the growth of aHSCs in vitro. The RGD inhibitors echistatin and GRGDS peptide and siRNA against the RGD receptor αVß1 resulted in the inhibition of aHSCs growth. Transduction of siRNAs against gp46, αVß1, and MT1-MMP to aHSCs inhibited the survival signal of PI3K/AKT/IκB. These results could provide novel antifibrosis strategies.

Low-affinity IgM antibodies lacking somatic hypermutations are produced in the secondary response of C57BL/6 mice to (4-hydroxy-3-nitrophenyl)acetyl hapten.

Class-switched memory B cells, which are generated through the processes of somatic hypermutation (SHM) and affinity-based selection in germinal centers, contribute to the production of affinity-matured IgG antibodies in the secondary immune response. However, changes in the affinity of IgM antibodies during the immune response have not yet been studied, although IgM(+) memory B cells have been shown to be generated. In order to understand the relationship between IgM affinity and the recall immune response, we prepared hybridomas producing anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) IgM antibodies from C57BL/6 mice and from activation-induced cytidine deaminase (AID)-deficient mice. Binding analysis by ELISA showed that mAbs obtained from the secondary immune response contained IgM mAbs with affinity lower than the affinity of mAbs obtained from the primary response. By analyzing sequences of the IgM genes of hybridomas and plasma cells, we found many unmutated VH genes. VH genes that had neither tyrosine nor glycine at position 95 were frequent. The repertoire change may correlate with the lower affinity of IgM antibodies in the secondary response. The sequence and affinity changes in IgM antibodies were shown to be independent of SHM by analyzing hybridomas from AID-deficient mice. A functional assay revealed a reciprocal relationship between affinity and complement-dependent hemolytic activity toward NP-conjugated sheep RBCs; IgM antibodies with lower affinities had higher hemolytic activity. These findings indicate that lower affinity IgM antibodies with enhanced complement activation function are produced in the secondary immune response.

Inhibition of CCL20 increases mortality in models of mouse sepsis with intestinal apoptosis.

BACKGROUND: CC chemokine ligand 20 (CCL20) and CC chemokine receptor 6 are believed to stimulate the recruitment of neutrophils and activation of macrophages against bacterial pathogens through the activation of T helper cells. We analyzed the role of CCL20 in the acute phase of sepsis. METHODS: The effect of a neutralizing, anti-mouse CCL20 monoclonal antibody (mAb) was examined in 2 murine models of sepsis: Cecal ligation and puncture (CLP) and Escherichia coli peritonitis. Immune cell migration, bacterial clearance, and expression of 17 cytokines and 5 chemokines were quantified in E coli-induced peritonitis. Expression of CCL20 in various tissues was determined, and apoptotic cells in jejunum were measured. RESULTS: Anti-CCL20 mAb increased mortality in CLP and E coli peritonitis (P = .029 and .024, respectively by Kaplan-Meier method and log-rank test). The 48-hour survival rate in anti-CCL20 mAb- and control immunoglobulin (Ig)G-treated mice was 37% (11/30) vs 62% (18/29) in CLP and 28% (11/40) vs 48% (19/40) in bacterial peritonitis. Neutralization of CCL20 showed no effect on leukocyte infiltration into the peritoneal cavity or bacterial clearance at 24 hours. CCL20 was induced strongly and predominantly in jejunum after bacterial infection, and neutralizing CCL20 increased apoptosis of epithelial cells in jejunum crypt. Inhibition of CCL20 increased serum tumor necrosis factor (TNF)-α (3.3-fold greater than control mice) and decreased serum interleukin (IL)-1α and IL-6. CONCLUSION: Neutralization of CCL20 before induction of sepsis increased mortality during sepsis accompanied with increasing epithelial apoptosis in the jejunum and augmenting serum TNF-α.

Characterization of memory B cells responsible for affinity maturation of anti- (4-hydroxy-3-nitrophenyl)acetyl (NP) antibodies.

We searched for memory B cells responsible for high-affinity anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) antibody production by C57BL/6 mice immunized with NP-chicken γ-globulin (CGG), using flow cytometry. We first prepared transfectants expressing B-cell antigen receptor (BCR) of known affinity as a memory B-cell model as well as NP-allophycocyanin (APC) of different NP valences, NP(lo), NP(med) and NP(hi). We then used the latter as probes capable of distinguishing BCR affinities: NP(lo)-APC bound to BCRs with an affinity higher than 3.4 × 10(6) M(-1), while NP(med)-APC bound to those with a higher than germline affinity. B cells capable of binding to NP(lo)-APC appeared in spleens on day 14 post-immunization, and harbored Tyr95 (Tyr95 type) as well as a mutation from Trp33 to Leu. B cells with BCRs harboring Gly95 (Gly95 type) appeared only in the NP(med)-APC-binding fraction on day 56 and in the NP(lo)-APC-binding fraction on day 77, indicating that this long duration was necessary for Gly95 type B cells to acquire high affinity and to become a member of the group of memory B cells with high affinity. Administration of NP-CGG on day 77 caused little change in the proportion of the Gly95 type in NP(lo)-APC-binding B cells in the following 2 weeks but brought about an increase in the number of high-affinity antibody-secreting cells (ASC), suggesting that the memory B-cell compartment established was maintained at a later stage and supplied high-affinity ASCs. The relationship between these Gly95 type memory B cells and ASCs is discussed.

The amino acid residue at position 95 and the third CDR region in the H chain determine the ceiling affinity and the maturation pathway of an anti-(4-hydroxy-3-nitrophenyl)acetyl antibody.

Two groups of anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) Abs each possessing a different amino acid, Tyr or Gly, at position 95, appeared respectively at early and late stages of immunization. The early Abs predominantly harbored Tyr95 and were referred to as the Tyr95 type. These had ∼100-fold lower ceiling affinity than the late Abs harboring Gly95, which were referred to as the Gly95 type. We found that in order to raise affinity, the Tyr95 type utilized a mutation at position 33 in V(H), while the Gly95 type used multiple mutations in both V(H) and V(L), and that the effect of the mutations was reciprocal; the former mutation had a positive effect on Tyr95 type Abs but a negative effect on Gly95 type Abs, and vice versa. The reciprocal effect of these mutations on affinity enabled us to assess the type of Abs prepared by introducing 20 different amino acids at position 95. We found that Abs harboring Lys95, Arg95, Pro95, and Tyr95 belonged to the Tyr95 type and those with Ala95 and Gly95, to the Gly95 type. Since this dependency on the amino acid at position 95 was observed in H chains whose third CDR (CDR 3H) consisted of 9 amino acids and not 11, the CDR 3H region was also considered to play an important role in determining the maturation pathway and the magnitude of the ceiling affinity.

Evaluation of the conformational equilibrium of reduced hen egg lysozyme by antibodies to the native form.

To evaluate the conformation of reduced HEL, the monoclonal antibodies HyC1 and HyC2, which recognize different conformational epitopes on native hen egg lysozyme (HEL), were used, and the kinetics of their interactions with native HEL, S-1,2-dicarboxyethylated HEL (DCE-HEL), and carboxymethylated Cys6 and Cys127 HEL (CM(6,127)-HEL) were assessed using surface plasmon resonance. Although their association rate constants differed 10(5)-fold, their dissociation rate constants were essentially the same, suggesting that DCE-HEL and CM(6,127)-HEL possess conformations similar to that of native HEL when they bind antibodies. We considered that the ratio of the association rate constant of reduced HEL to native HEL represents the proportion of the native format determinant in equilibrium. Reduction of the Cys6-Cys127 disulfide bond would transform the epitope recognized by HyC1 into a non-native conformation similar to that of DCE-HEL. We show that monoclonal antibodies provide a sensitive tool for evaluation of the structural and hydrodynamic changes of proteins.

Role of CX3CL1/fractalkine in osteoclast differentiation and bone resorption.

The recruitment of osteoclast precursors toward osteoblasts and subsequent cell-cell interactions are critical for osteoclast differentiation. Chemokines are known to regulate cell migration and adhesion. CX3CL1 (also called fractalkine) is a unique membrane-bound chemokine that has dual functions for cells expressing its receptor CX3CR1: a potent chemotactic factor in its soluble form and a type of efficient cell adhesion molecule in its membrane-bound form. In this paper, we demonstrate a novel role of CX3CL1 in osteoblast-induced osteoclast differentiation. We found that osteoclast precursors selectively expressed CX3CR1, whereas CX3CL1 is expressed by osteoblasts. We confirmed that soluble CX3CL1 induced migration of bone marrow cells containing osteoclast precursors, whereas immobilized CX3CL1 mediated firm adhesion of osteoclast precursors. Furthermore, a blocking mAb against CX3CL1 efficiently inhibited osteoclast differentiation in mouse bone marrow cells cocultured with osteoblasts. Anti-CX3CL1 also significantly suppressed bone resorption in neonatal mice by reducing the number of bone-resorbing mature osteoclasts. Collectively, CX3CL1 expressed by osteoblasts plays an important role in osteoclast differentiation, possibly through its dual functions as a chemotactic factor and adhesion molecule for osteoclast precursors expressing CX3CR1. The CX3CL1-CX3CR1 axis may be a novel target for the therapeutic intervention of bone resorbing diseases such as rheumatoid arthritis, osteoporosis, and cancer bone metastasis.

Chemokines as novel therapeutic targets for inflammatory bowel disease.

The inflammatory bowel diseases (IBD) such as Crohn's disease (CD) and ulcerative colitis (UC) are illness characterized by a chronic clinical course of relapse and remission associated with self-destructive inflammation of the gastrointestinal tract. In both UC and CD, leukocyte infiltration into the intestine is fundamental event in disease development and progression where the chemokines and their receptors are orchestrating the tissue-specific and the cell type-selective trafficking of leukocytes. In this review, we will discuss the homeostatic and inflammatory roles of the chemokines and their receptors with their potentials and promise as molecular targets for therapeutic interventions in human IBD, focusing on the recently identified role of the CX3CL1-CX3CR1 axis, as well as the CCL20-CCR6, CCL25-CCR9, and CXCL10-CXCR3 pathways.

Differences in neurogenic potential in floor plate cells along an anteroposterior location: midbrain dopaminergic neurons originate from mesencephalic floor plate cells.

Directed differentiation and purification of mesencephalic dopaminergic (mesDA) neurons from stem cells are crucial issues for realizing safe and efficient cell transplantation therapies for Parkinson's disease. Although recent studies have identified the factors that regulate mesDA neuron development, the mechanisms underlying mesDA neuron specification are not fully understood. Recently, it has been suggested that mesencephalic floor plate (FP) cells acquire neural progenitor characteristics to generate mesDA neurons. Here, we directly examined this in a fate mapping experiment using fluorescence-activated cell sorting (FACS) with an FP cell-specific surface marker, and demonstrate that mesencephalic FP cells have neurogenic activity and generate mesDA neurons in vitro. By contrast, sorted caudal FP cells have no neurogenic potential, as previously thought. Analysis of dreher mutant mice carrying a mutation in the Lmx1a locus and transgenic mice ectopically expressing Otx2 in caudal FP cells demonstrated that Otx2 determines anterior identity that confers neurogenic activity to FP cells and specifies a mesDA fate, at least in part through the induction of Lmx1a. We further show that FACS can isolate mesDA progenitors, a suitable transplantation material, from embryonic stem cell-derived neural cells. Our data provide insights into the mechanisms of specification and generation of mesDA neurons, and illustrate a useful cell replacement approach for Parkinson's disease.