Articular cartilage depicted at optimized angular position of Laue angular analyzer by X-ray dark-field imaging

Using 36.0 keV X-ray from synchrotron radiation, we examined the optimized angular position of Laue analyzer for depicting articular cartilage of an intact human finger by X-ray dark-field imaging. The surface of articular cartilage was depicted clearly by adopting the offset angle of 0.04 arcsec to lower angular side to the analyzer whilst the contour of articular cartilage was delineated clearly at the other angular positions of the analyzer within the width of the rocking curve.

Accurate diagnosis of musculoskeletal lesions by core needle biopsy

BACKGROUND

Percutaneous needle biopsy has many advantages over open biopsy in the treatment of neoplasms. However, the accuracy of needle biopsy in the diagnosis of musculoskeletal lesions has not yet been established. Here, we evaluate the accuracy and limitations of the procedure for musculoskeletal lesions.

METHODS

The diagnoses of 163 needle biopsies (bone, 91; soft tissue, 72) performed on 157 consecutive patients using a Jamshidi needle or an Ostycut needle for bone lesions, or a Tru-cut needle for soft tissue lesions were compared with the final diagnoses made by open biopsy and/or a definitive operation.

RESULTS

One hundred forty-three specimens (88%) were determined to be adequate for histological examination. Obtaining undamaged cores from very hard bony lesions or sclerotic cyst walls proved difficult. A pathologist with experience in musculoskeletal lesions was able to differentiate malignant tumors from benign lesions in 97% of the cases (bone, 100%; soft tissue, 94%) and arrive at a specific diagnosis in 88% (bone, 96%; soft tissue, 78%) when adequate cores were obtained. Differentiating a well-differentiated liposarcoma from a benign lipoma and inflammatory lesions from benign tumorous conditions, was difficult. The overall accuracy was 77% (bone, 85%; soft tissue, 68%). There was no morbidity related to the procedure.

CONCLUSION

The results indicate that needle biopsy is safe and accurate for diagnosing musculoskeletal lesions.

Chromosomal and genetic imbalances in synovial sarcoma detected by conventional and microarray comparative genomic hybridization

PURPOSE

To analyze the relationship between chromosomal instabilities and clinicopathological factors in synovial sarcoma (SS).

METHODS

Twenty-two fresh-frozen SS were analyzed by metaphase comparative genomic hybridization (CGH). Additional microarray CGH was performed in 13 cases.

RESULTS

Fourteen patients with SYT-SSX1 rearrangements and nine patients with biphasic tumor subtypes had better prognosis than the eight patients with SYT-SSX2 rearrangements and 13 patients with monophasic subtypes, respectively. Gains (average 3.0) were more frequent than losses (average 1.0). Frequent gains were identified on chromosomal regions 2, 6q, 7, 8q, 12, 17q, 18q, and 21q, whereas frequent losses were over-lapped on chromosomes 1p31-p35, 3p, 6q, 16, and 17p. High-level gains were observed on chromosomes 1q21-q31, 7, 8, 12, 17q, 18q, and 21q. Thirteen monophasic and nine biphasic tumors had an average of 5.1 and 2.8 aberrations, respectively. Patients with tumors harboring numerous aberrations (>or=3) had a worse clinical course. Microarray CGH more specifically detected genetic imbalances including gains in MDM2, MSH2, KCNK12, DCC, CDK2, ERBB3, SAS, and CDK4 and losses in HRAS, RASSF1, and CCND1. Gain of SAS was an important prognostic factor of SS.

CONCLUSION

We have identified several factors influencing the prognosis of SS patients by metaphase and microarray CGH.

Magnetic resonance angiography without contrast enhancement medium in bone and soft tissue tumors

The aim of this study was to assess the ability of a new magnetic resonance (MR) angiography technique that does not use contrast enhancement medium to depict the vascularity of musculoskeletal neoplasms, and evaluate its clinical utility. We performed 3D fresh blood imaging (FBI) MR angiography in 57 patients with bone or soft tissue tumors, and the detection of vessels in and around the tumor was evaluated. Moreover, differences in vascularity between benign and malignant tumors were analyzed. In the lower leg, large arteries such as femoral or popliteal arteries were visible. In the trunk or arm, large vessels such as subclavian or iliac arteries were visible. Discrimination between benign and malignant tumors was impossible in bone tumors; however, the mean value of vascularity differed between benign and malignant tumors in the soft tissue tumors. This is the first trial of the FBI method for bone and soft tissue tumors. The still developing method of MRA without contrast materials could clearly depict major arteries in the trunk and the extremities, this method may replace conventional MRA of bone and soft tissue tumors because it produces vivid images while being non-invasive.

Chromosomal imbalances in malignant peripheral nerve sheath tumor detected by metaphase and microarray comparative genomic hybridization

Malignant peripheral nerve sheath tumors (MPNSTs) are highly malignant tumors affecting adolescents and adults. There have been a few reports on chromosomal aberrations of MPNSTs; however, the tumor-specific alteration remains unknown. We characterized the genomic alterations in 8 MPNSTs and 8 schwannomas by metaphase comparative genomic hybridization (CGH). In 5 of 8 MPNSTs, microarray CGH was added for more detailed analyses. Frequent gains were identified on 3q13-26, 5p13-14, and 12q11-23 and frequent losses were at 1p31, 10p, 11q24-qter, 16, and 17. Microarray CGH revealed frequent gains of EGFR, DAB2, MSH2, KCNK12, DDX15, CDK6, and LAMA3, and losses of CDH1, GLTSCR2, EGR1, CTSB, GATA3, and SULT2A1. These genes seem to be responsible for developing MPNSTs. The concordance rate between metaphase CGH and microarray CGH was 66%. Metaphase CGH was useful for identifying chromosomal alterations before applying microarray CGH.

Novel transdermal photodynamic therapy using ATX-S10·Na(II) induces apoptosis of synovial fibroblasts and ameliorates collagen antibody-induced arthritis in mice

We aimed to test the effect of transdermal photodynamic therapy (PDT) on synovial proliferation in vitro and in vivo, using a novel photosensitizer, ATX-S10.Na(II). Synovial fibroblasts were obtained from patients with RA (RASF). Cell viability with or without PDT was determined by MTT assay. Cell morphology was examined by light and transmission electron microscopy. DNA fragmentation was labeled by TUNEL stain. Collagen antibody-induced arthritis (CAIA) was induced in DBA/1 mice, and the effects of transdermal PDT were evaluated by clinical and histological examination. PDT showed drug concentration-dependent and laser dose-dependent cytotoxicity on RASF. TUNEL stain and TEM study revealed the induction of apoptotic cell death of RASF. Transdermal PDT significantly reduced clinical arthritis and synovial inflammation in this model of arthritis. These results suggest that transdermal PDT using ATX-S10.Na(II) might be a novel less invasive treatment strategy for small joint arthritis and tenosynovitis.

Calpain inhibitors prevent neuronal cell death and ameliorate motor disturbances after compression-induced spinal cord injury in rats

Traumatic spinal cord injury (SCI) results in widespread neuronal cell death. Recent studies have suggested that activated calpain mediates neuronal cell death in the central nervous system. We conducted a study to determine whether calpain mediates neuronal cell death in the motor neurons of the spinal cord after SCI, and whether postinjury administration of the calpain inhibitors N-acetyl- Leu-Leu-Met-CHO (ALLM) and calpain inhibitor III (CI III) (MDL28170) reduces the motor disturbances in rats with a model of SCI. Adult male Wistar rats were subjected to SCI by application of a 20-g weight impactor probe to the spinal cord at T12 for 20 min. The rats were divided into three groups according to whether they were injected intravenously with 0.05-2.5 mg/kg ALLM, 10 mg/kg CI III, or 0.1% DMSO as a control every 24 h for 1 week after SCI. Calpain was activated in the spinal cord at 8 h, 24 h, and 5 days after SCI, and administration of ALLM inhibited its activation. ALLM, as compared to the DMSO vehicle alone, also significantly reduced the number of motor neurons in spinal-cord lesions that were positively labeled at 24 h after SCI with the terminal deoxynucleotidyl transferase-uridine nucleotide end-labeling (TUNEL) technique. Additionally, both the inclined plane test and footprint analysis showed markedly better motor activity after 4 weeks in rats injected with ALLM or CI III than in rats given vehicle only. These results suggest that activation of calpain plays a critical role in the neuronal cell death that follows SCI, and that calpain inhibitors may have benefit in treating the motor disturbances that follow SCI.

The role of thallium-201 and pentavalent dimercaptosuccinic acid for staging cartilaginous tumours

Introduction

Heterogeneity of cartilage tumours may confound accurate diagnosis and grading resulting in under and over treatment. Improved preoperative assessment of malignancy and grade would be invaluable for developing a rational plan for treatment. We examined correlations between nuclear tracer avidity and malignancy grade in cartilage tumours.

Methods

Between 1996 and 2000, 92 consecutive patients with cartilaginous tumours (50 benign, 42 non-metastatic malignant) underwent nuclear scanning. Thallium-201 (TL-201) and pentavalent dimercaptosuccinic acid (DMSAV) were used as nuclear isotopes. Scanning with these agents was performed on separate days 48 hours apart. Static and SPECT images were obtained at 30 m and 4 h after injection of nuclear tracer. Pathology review was undertaken blinded to the results of the nuclear scans and correlations between histologic results and trace uptake at 4 hours examined.

Results

25 patients with negative DMSAV had benign tumours. 15/17 tumours with positive TL-201 had malignant tumours. 11/13 patients with both positive DMSAV and TL-201 scans had intermediate or high grade tumours and 4 of these developed metastases. We have developed an algorithm for the management of patients with tumours that aims to avoid over treatment of low grade tumours and under treatment of high grade tumours.

Conclusion

Functional nuclear scanning with TL-201 and DMSAV complements other imaging modalities in the management of cartilaginous tumours.

Amplification of MYCL in Atypical Ewing Tumor. Analysis of Metaphase and Microarray Comparative Genomic Hybridization

A 20-year-old man developed a soft tissue mass in his right upper arm and, 3 months later, was referred to our hospital. The tumor cells showed brisk mitotic activity and a large amount of cytoplasmic glycogen was demonstrated with periodic acid Schiff stain. A diagnosis of atypical Ewing sarcoma was made. Chemotherapy according to the VACA protocol, comprising vincristine, actinomycin D, cyclophosphamide and doxorubicin was started. The chemotherapy was effective and a limb salvage procedure was performed by implantation of an autoclaved bone after wide tumor excision. During the postoperative chemotherapy, a local recurrence and multiple metastases developed, and the patient died due to disease progression. Fourteen years later, this tumor sample, preserved in a deep-freeze, was analyzed by reverse-transcriptase polymerase chain reaction (RT-PCR) to detect the fusion gene. This tumor had an EWS exon 7 to FLI1 exon 6 fusion transcript. Moreover, metaphase and microarray comparative genomic hybridization (CGH) was done to detect chromosomal instabilities. Many gains and losses were noted on metaphase CGH, and MYCL amplification was identified on microarray CGH.

Influence of telomerase activity on bone and soft tissue tumors

PURPOSE

Telomeres consisting of a repeating nucleotide sequence (TTAGGG)n are shortened in normal somatic cells. Telomerase is an enzyme that elongates the telomere sequence and is detected in most human cancers and usually not in normal somatic cells. Little is known about telomerase activity in bone and soft tissue tumors. The aim of this study was to investigate the relationship between telomerase activity and clinical factors in bone and soft tissue tumors.

METHODS

Telomerase activity was measured using the modified telomeric repeat amplification protocol (TRAP) assay in 115 bone and soft tissue tumors obtained through open biopsy or resection.

RESULTS

Telomerase activity was detected in 10% of benign tumors and 44% of malignant tumors (p < 0.001). A higher incidence of telomerase activity was detected in high-grade tumors than in low-grade tumors (p = 0.002). The cumulative metastasis-free and overall survival in telomerase-positive patients was significantly worse than in telomerase-negative patients (p = 0.045 and p = 0.048).

CONCLUSION

Our study suggests that telomerase activity is associated with tumor aggressiveness and may be a useful parameter to predict the prognosis of patients with malignant bone and soft tissue tumors.

Extended total sacrectomy and reconstruction for sacral tumor

STUDY DESIGN

This case report includes the results of long-term follow-up after extended total sacrectomy in a 13-year-old boy with a sarcoma originating in the sacrum with an extraskeletal extension and infiltration into the left ilium.

OBJECTIVE

To report and discuss a case of sacral tumor treated by extended sacrectomy.

SUMMARY OF BACKGROUND DATA

Sacral tumors are often at an advanced stage with a large volume at diagnosis. Although total or extended sacrectomy is the only radical means to treat the massive sacral tumor, unavoidable complications in total sacrectomy are serious in the treatment selection.

METHODS

Initial histologic findings indicated a synovial sarcoma. Additional genetic analysis redesignated the tumor as an unclassified sarcoma. Preoperative neoadjuvant chemotherapy and radiotherapy were completed. The response to the preoperative treatment appeared as a reduction in tumor size (approximately 50%) on radiographs. After extended sacrectomy, the L5 vertebral body was fixed between the ilia, and the pelvic ring was compressed by the Zielke system. The ISOLA instrumentation system connected the lumbar spine and both ilia. All sacral nerve roots and the L5 root on the left side were cut.

RESULTS

At the 5-year follow-up examination, the patient was disease-free, could walk with crutches, and could climb stairs using the handrail and one crutch.

CONCLUSIONS

The patient's excellent response to preoperative antitumor treatment was considered crucial to the long-term outcome. But the decision between a radical resection with reconstruction and a less extensive procedure with combined therapy remains controversial.

In vitro antiseptic susceptibility of clinical isolates from nosocomial infections

To evaluate the susceptibility of a large number of strains to various antiseptics, we elaborated a simple, qualitative broth turbidity method in which we could quickly judge the efficacy visually. For this method, we prepared a modified neutralizer broth, consisting of trypticase soy broth containing 15% Tween 80, 1% soybean lecithin and 0.5% sodium thiosulfate. The susceptibilities of Serratia marcescens No. 26 to 4 antiseptics obtained from the turbidity method showed a good agreement with those obtained from the colony-counting method; the 4 antiseptics tested were povidone-iodine (PVP-I), chlorhexidine gluconate (CHG), benzalkonium chloride (BAC) and alkyldiaminoethylglycine hydrochloride (AEG). Both PVP-I and BAC had complete efficacy in 0.5 min against all isolates tested [100 isolates of S. marcescens, 103 of Klebsiella pneumoniae, 99 of Pseudomonas aeruginosa, 19 of Alcaligenes faecalis and 30 of A. xylosoxidans subsp. xylosoxydans (A. xylosoxydans)]. In contrast, the effectiveness of CHG was weak compared with PVP-I, BAC and AEG. Strong resistance against AEG was noted even after 3-min exposure in 1 isolate each of A. faecalis and A. xylosoxydans. It is concluded that the turbidity test is a simple and accurate method to evaluate susceptibility to various antiseptics and that it is suitable for a screening of a large number of strains. Among the 4 antiseptics tested, PVP-I and BAC showed a consistently high activity against all isolates, confirming PVP-I and BAC to be clinically useful antiseptics.

Inhibition of human chondrosarcoma cell growth via apoptosis by peroxisome proliferator-activated receptor-gamma

A rare immunohistochemical study using 28 surgical sections of human chondrosarcoma revealed that 67.9% of tumour cells had weak (10-40%) or strong (>40%) positive immunoreaction for peroxisome proliferator-activated receptor-gamma. The expression of peroxisome proliferator-activated receptor-gamma mRNA and protein in human chondrosarcoma cell line OUMS-27 was also determined by reverse transcription-polymerase chain reaction and immunocytochemistry, respectively. Furthermore, the effects of peroxisome proliferator-activated receptor-gamma ligands on cell proliferation and survival were investigated in OUMS-27 cells. Pioglitazone, a selective ligand for peroxisome proliferator-activated receptor-gamma, and 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), a putative endogenous ligand for peroxisome proliferator-activated receptor-gamma, inhibited the proliferation of OUMS-27 cells in a dose-dependent manner. The mechanism of cytotoxic effects of 15d-PGJ(2) was via apoptosis as shown by DNA fragmentation using TUNEL stain and DNA ladder formation, and by ultrastructural analysis using transmission electron microscopy. Flow-cytometric analysis using annexin-V-fluorescein and propidium iodide detected the early change of apoptosis, as well as necrosis of OUMS-27 cells at 4 h after co-incubation with 15d-PGJ(2). These results suggest that peroxisome proliferator-activated receptor-gamma may play a significant role in the pathogenesis of chondrosarcoma, and peroxisome proliferator-activated receptor-gamma ligands, especially 15d-PGJ(2), may be of therapeutic value in the treatment of human chondrosarcoma.

Co-expression of parathyroid hormone-related protein (PTHrP) and PTH/PTHrP receptor in cartilaginous tumours: a marker for malignancy?

AIM

Parathyroid hormone-related protein (PTHrP) is one of the critical factors for the differentiation and growth of chondrocytes. We examined the correlation between the co-expression of PTHrP and PTH/PTHrP receptor and the grade of malignancy in cartilaginous tumours.

METHODS

We analysed PTHrP and PTH/PTHrP receptor expression in chondrosarcoma by immunohistochemistry and compared specific staining with the expression in benign cartilaginous tumours. There were 38 cartilaginous bone tumours consisting of 26 chondrosarcoma, six enchondroma and six osteochondroma. Chondrosarcoma were composed of 20 conventional chondrosarcoma (10 grade 1, seven grade 2, and three grade 3), two dedifferentiated chondrosarcoma, two clear cell chondrosarcoma, and two myxoid chondrosarcoma. We performed the standard peroxidase-labelled streptavidin-biotin detection method for immunohistochemistry using an antibody raised against PTHrP (1-14) and PTH/PTHrP receptor. The magnitude of receptor positivity of PTHrP and PTH/ PTHrP in each tumour was assessed as a percentage of PTHrP and PTH/PTHrP-positive cells per thousand tumour cells in the most histologically aggressive area of the tumour.

RESULTS

All chondrosarcoma, five of six enchondroma, and four of six osteochondroma showed PTHrP-positive cells, and all chondrosarcoma, five of six enchondroma and five of six osteochondroma showed PTHrP receptor-positive cells. The grade of malignancy correlated with the percentage of both PTHrP and PTH/PTHrP receptor-positive tumour cells (P < 0.0001, either). Each grade of chondrosarcoma showed statistically higher expression of both PTHrP and PTH/PTHrP receptor than benign cartilaginous tumour.

CONCLUSION

This is the first report of the co-expression of PTHrP and PTH/PTHrP receptor in chondrosarcoma. PTHrP and PTH/PTHrP receptor positivity may be valuable for differentiating between benign and malignant cartilaginous tumours.

Endostatin inhibits adhesion of endothelial cells to collagen I via alpha(2)beta(1) integrin, a possible cause of prevention of chondrosarcoma growth

Endostatin derived from collagen XVIII is a potent endogenous anti-angiogenic factor that induces regression of various tumors of epithelial origin. Endostatin has been shown to inhibit endothelial cell functions, however, its effect remains controversial. We first attempted here to apply the inhibitory effect of recombinant human endostatin on chondrosarcomas, which originate from the mesenchyme, in nude mice. Endostatin induced reduction of chondrosarcoma growth and tumor angiogenesis in vivo. However, endostatin showed no effect on the proliferation and migration of chondrosarcoma cells in vitro. Next, we investigated the interactions between endostatin and endothelial cells in detail. Endostatin inhibited the migration on and attachment to collagen I but did not affect the proliferation of endothelial cells. Although the migration of endothelial cells was stimulated by angiogenic factors such as basic fibroblast growth factor and vascular endothelial growth factor, endostatin showed similar inhibitory effects on it in the presence and absence of the stimulants. Moreover, the inhibitory effect against endothelial cell attachment to collagen I was attenuated or modulated in the presence of neutralizing antibodies of alpha(2), alpha(5)beta(1), and alpha(V)beta(3) integrins but not that of alpha(1) integrin. Our results suggest that endostatin might suppress the alpha(2)beta(1) integrin function of endothelial cells via alpha(5)beta(1) or alpha(V)beta(3) integrin. We propose here that endostatin might be effective for anti-angiogenic therapy for human chondrosarcomas through the suppression of alpha(2)beta(1) integrin functions in endothelial cells.

Wound complications following pre-operative radiotherapy for soft tissue sarcoma

AIMS

We analysed wound complications in 43 patients with soft tissue sarcoma who were treated with combined pre-operative radiotherapy and surgery.

METHODS

All patients received the same protocol of pre-operative radiotherapy at our institution.

RESULTS

Thirty-six (84%) patients developed acute skin toxicity following radiotherapy. After wide local excision, 15 patients required primary soft tissue reconstruction with vascularized muscle transfer and four patients underwent free skin flap to enable wound closure as part of their primary surgery. Nineteen patients (44%) developed post-operative wound complications including 10 (23%) patients who required an additional surgical procedure. Four (27%) patients developed flap necrosis in a group of 15 who underwent primary vascularized soft tissue transfer. All required a second vascularized muscular flap. One elderly patient, who had grade 3 acute radiation skin toxicity, had an arterial graft and total hip arthroplasty for a femoral artery aneurysm and an avascular necrosis of the hip, respectively. In our series, age (> or = 40 years) was the only impact factor influencing wound complication after surgery following radiotherapy (P=0.06).

CONCLUSIONS

Site of tumour, radiation field size, surgical resection volume, grade of acute radiation toxicity, co-morbidity, and smoking were not demonstrated to have predictive value in wound complication following pre-operative radiotherapy. Although previous papers suggested that vascularized soft tissue transfer could be useful reducing wound morbidity, our results could not confirm this.

Review: ligands for receptor tyrosine kinases expressed in the skin as environmental factors for melanocyte development

Skin is the major tissue where melanocytes develop, and skin keratinocytes provide the necessary micro-environment for melanocyte survival, proliferation, differentiation, and migration. In this paper, we will discuss the ligands for receptor tyrosine kinases produced as environmental cues to support melanocyte development in the skin.

Review: melanocyte migration and survival controlled by SCF/c-kit expression

Melanocytes are derived from neural crest and migrate along the dorsolateral pathway to colonize the final destination in the skin. Stem cell factor and its receptor c-kit were identified as gene products of Sl and W mutant loci; both of them were known to have defects in melanocytes survival. In this review, we focus on the function of stem cell factor and c-kit in melanocyte migration and survival, which has become clearer in the last decade. By analysis of both molecules in wild-type and white spotting mutant mice, ligand and receptor set were shown to play multiple roles in the development of melanocytes in mouse ontogeny. Functional blockade of c-kit by specific monoclonal antibody illustrated distinct c-kit dependent and independent stages in melanocyte development. Finally, SCF transgene expression demonstrated that part of the c-kit dependent step is regulated by spatiotemporally specific ligand expression and also indicated the presence of c-kit independent melanocyte stem cells in postnatal skin.

Tumor-specific cytotoxic T lymphocyte responses against chondrosarcoma with HLA haplotype loss restricted by the remaining HLA class I allele

Although loss of HLA expression by malignant cells has also been demonstrated, it has not been clarified how the loss of HLA expression observed in vitro actually results in immune escape. We demonstrated two major findings: (i) a part of chromosome 6 coding for HLA haplotypes was deleted from the genome of chondrosarcoma cell line, OUMS-27; furthermore, immunohistostaining for HLA-A11 showed that the original chondrosarcoma tissue lost the expression of HLA-A11, implicating that HLA haplotype loss was already present in the original tumor tissue and (2) HLA class I-restricted and autologous tumor-specific cytotoxic T cells (CTL) were generated from peripheral blood lymphocytes of the patient with chondrosarcoma, from whom OUMS-27 originated. This CTL line was maintained by weekly stimulation with OUMS-27, and lysed OUMS-27 in an HLA-A24 dependent manner but did not either K562 or autologous (EBV)-transformed B cells. These observations indicated that OUMS-27 and its original tumor are still immunogenic and can present antigen peptides with the remaining HLA-A24, even if HLA expression is partially lost. Tumor specific immunotherapy can be applied to the treatment of malignancies, even if HLA expression is partially lost.

Wnt signaling regulates hemopoiesis through stromal cells

Hemopoietic cells develop in a complex milieu that is made up of diverse components, including stromal cells. Wnt genes, which are known to regulate the fate of the cells in a variety of tissues, are expressed in hemopoietic organs. However, their roles in hemopoiesis are not well characterized. In this study, we examined the roles of Wnt proteins in hemopoiesis using conditioned medium containing Wnt-3a. This conditioned medium dramatically reduced the production of B lineage cells and myeloid lineage cells, except for macrophages in the long-term bone marrow cultures grown on stromal cells, although the sensitivity to the conditioned medium differed, depending on the hemopoietic lineage. In contrast, the same conditioned medium did not affect the generation of B lineage or myeloid lineage cells in stromal cell-free conditions. These results suggested that Wnt proteins exert their effects through stromal cells. Indeed, these effects were mimicked by the expression of a stabilized form of beta-catenin in stromal cells. In this study, we demonstrated that Wnt signaling regulates hemopoiesis through stromal cells with selectivity and different degrees of the effect, depending on the hemopoietic lineage in the hemopoietic microenvironment.

Skin antigens in the steady state are trafficked to regional lymph nodes by transforming growth factor-beta1-dependent cells

Antigen capturing in the skin and antigen trafficking into regional lymph nodes (LN) initiate immune responses. In this study, employing melanin granule (MG) as an easily traceable antigen in two mouse strains that carried steel factor or hepatocyte growth factor transgenes and had melanocytosis in the epidermis or in the dermis respectively, we investigated the mechanism of antigen trafficking from the skin. MG captured in the epidermis or dermis accumulated in the regional LN, but not other tissues. Only in alymphoplastic mice did MG-laden cells pass through the lymphatics and reached many tissues. Since inflammatory regions were not observed in the skin of either type of transgenic mouse, our developmental system enables us to investigate constitutive capturing and trafficking of insoluble antigens in the steady state. Both dendritic cells and macrophages were laden with MG in the regional LN. To determine which cells traffic antigens to the LN, we prepared double mutants that carried the transgenes and lacked transforming growth factor (TGF)-beta1, since mice lacking TGF-beta1 are reported to be deficient of Langerhans cells. Few MG were observed in the regional LN of these double-mutant mice. We also showed that signaling via macrophage colony stimulating factor receptor or Flt3/Flk2 is not essential for development of the cells for this antigen trafficking. These results indicate that antigens in the epidermis and dermis in the steady state are trafficked into regional LN only by TGF-beta1-dependent cells, which may be a dendritic cell lineage.