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We have isolated a murine cDNA encoding a 9-kD protein, Chisel (Csl), in a screen for transcriptional targets of the cardiac homeodomain factor Nkx-25. Csl transcripts were detected in atria and ventricles of the heart and in all skeletal muscles and smooth muscles of the stomach and pulmonary veins. Csl protein was distributed throughout the cytoplasm in fetal muscles, although costameric and M-line localization to the muscle cytoskeleton became obvious after further maturation. Targeted disruption of Csl showed no overt muscle phenotype. However, ectopic expression in C2C12 myoblasts induced formation of lamellipodia in which Csl protein became tethered to membrane ruffles. Migration of these cells was retarded in a monolayer wound repair assay. Csl-expressing myoblasts differentiated and fused normally, although in the presence of insulin-like growth factor (IGF)-1 they showed dramatically enhanced fusion, leading to formation of large dysmorphogenic 'myosacs.' The activities of transcription factors nuclear factor of activated T cells (NFAT) and myocyte enhancer--binding factor (MEF)2, were also enhanced in an IGF-1 signaling-dependent manner. The dynamic cytoskeletal localization of Csl and its dominant effects on cell shape and behavior and transcription factor activity suggest that Csl plays a role in the regulatory network through which muscle cells coordinate their structural and functional states during growth, adaptation, and repair. Key words: costameres * heart * lamellipodia * Nkx2-5 * skeletal muscle

Regulated emigration of blood-borne leukocytes plays a defining role in lymphoid organ development, immune surveillance, and inflammatory responses. We report here that mice deficient in the homeobox gene Nkx2-3, expressed in developing visceral mesoderm, show a complex intestinal malabsorption phenotype and striking abnormalities of gut-associated lymphoid tissue and spleen suggestive of deranged leukocyte homing. Mutant Peyer's patches were reduced in number and size, intestinal villi contained few [IgA.sup.+] plasma cells, and mutant spleens were small and often atrophic, showing fused periarterial lymphoid sheaths, partially merged T and B cell zones, an absent marginal zone, and a dearth of macrophages in red pulp. Semiquantitative RT-PCR analysis and immunohistochemistry revealed down-regulation of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in endothelial cells in which Nkx2-3 is normally expressed. MAdCAM-1 is a member of the immunoglobulin superfamily, acting as an endothelial cell ligand for leukocyte homing receptors L-selectin and [Alpha]4[Beta]7 integrin. Our data suggest a role for a homeodomain factor in establishing the developmental and positional cues in endothelia that regulate leukocyte homing through local control of cellular adhesion and identify MAdCAM-1 as a candidate target gene of Nkx2-3. [C] 2000 Academic Press Key Words: NK-2; Nkx2-3; homeobox; leukocyte homing; lymphocyte homing; MAdCAM-1; spleen; Peyer's patches; lamina propria.

This study is to investigate the protective effects of the SB203580 against radiation induced mortality and intestinal injury of mice. A total of 67 male C57BL/6 mice (20.0-22.0 g) were matched according to body weight and randomly assigned to one of three groups: control, total body irradiation exposure (IR, 7.2 Gy) only, and IR (7.2 Gy) + SB203580 (15 mg x kg(-1)). 30 days survival rate was observed in the experiment. In intestinal injury experiment, the expression levels of caspase-3, Ki67, p53 and p-p38 were assayed in the mice intestine crypts. The results showed that the 30 days survival rate was 100% (control), 0 (IR) and 40% (IR+ SB203580), separately. Compared to the IR groups, the positive cells of caspase-3, p53 and p-p38 in crypt cells decreased 33.00%, 21.78% and 34.63%, respectively. The rate of positive cells of Ki67 increased 37.96%. Significant difference was found between all of them (P < 0.01). SB203580 potently protected against radiation-induced lethal and intestinal injury in mice, and it may be a potential radio protector.

VAMP8, a member of the soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) family of fusion proteins, initially characterized in endosomal and endosomal-lysosomal fusion, may also function in regulated exocytosis. VAMP8 physiological function in inflammation has not been elucidated. In this paper, we show that deficiency of VAMP8 protects mice from anaphylatoxin (C5a)-induced neutropenia, peritonitis, and systemic inflammation. We show that, in vivo, VAMP8 deletion inhibits neutropenia and phagocyte recruitment. We also show that in macrophages, VAMP8 localizes on secretory granules and degranulation is inhibited in VAMP8-deficient macrophages. Moreover, VAMP8(-/-) mice show reduced systemic inflammation with inhibition of serum TNF-alpha levels, whereas IL-1beta, IL-6, and MIP1alpha release are not affected. In wild-type macrophages, TNF-alpha colocalizes with VAMP8-positive vesicles, and in VAMP8-deficient macrophages, the TNF-alpha release is inhibited. Furthermore, VAMP8 regulates the release of TNF-alpha and beta-hexosaminidase triggered by fMLP, and VAMP8(-/-) mice are protected from fMLP-induced peritonitis. These data demonstrate that the VAMP8 vesicle-associated-SNARE is required for the proper trafficking of secretory lysosomal granules for exocytosis in macrophages and for the release of the potent proinflammatory cytokine, TNF-alpha.

Objective: To extract and analysis the active components of Se-protein polysaccharide from Se-rich Cordyceps militaris, and to discuss the anti-tumor effect of Se-protein polysaccharide., Method: Protein, polysaccharides and selenium content were determined by the methods of Folin-phenol reagent (lowry), phenol-sulfate and DAN fluorescence, respectively. Tumor-bearing mouse model was established and divided into the model group, cyclophosphamide group, cordyceps high and low dosage group (200, 100 mg x kg(-1)). Then the Se-protein polysaccharide's anti-tumor activity and immune function in vivo were observed by compare with model group in the weight of mice, inhibitory rate, conversion rate of peripheral blood lymphocytes, dissection index K, swallowed factor alpha, liver and spleen factor coefficient, GSH-Px and SOD activity and the content of MDA., Result: Se-protein polysaccharides from Se-rich Cordyceps militaris had a significant anti-tumor action with the inhibitory rate 46.92% and could avoid toxic effect of chemotherapy drug like cyclophosphamide. It also could enhance immune function and body antioxidant capacity by inhibiting the decline of tumor-bearing mouse liver coefficient and spleen coefficient in tumor-bearing mice caused by cyclophosphamide., Conclusion: Se-protein polysaccharide, the extraction of Se-rich Cordyceps militaris's can inhibit tumor grouth of tumor-bearing mouse.

Head development in vertebrates requires reciprocal patterning interactions between cranial neural crest and the ectodermal, mesodermal and endodermal components of the branchial arches. Patterning elements within the pharyngeal endoderm and oral ectoderm appear to play defining roles in this process. Several homeobox genes of the NK-2 class (Nkx2-1, Nkx2-3, Nkx2-5 and Nkx2-6) are expressed regionally in the developing pharynx, and Nkx2-1 mutants and Nkx2-5/Nkx2-6 double mutants show loss of thyroid and distal lung progenitors, and pharyngeal cell viability, respectively. Here we examined the expression and genetic role of Nkx2-3 in pharyngeal development. Nkx2-3 was expressed in the pharyngeal floor and pouches, as well as in oral and branchial arch ectoderm. Expression persisted in the developing thyroid until birth, in mucous-forming cells of the lingual and sublingual salivary glands, and in odontogenic epithelium of the mandible. Examination of Nkx2-3 null mice revealed defects in maturation and cellular organisation of the sublingual glands. Furthermore, cusps were absent from mandibular molars and the third molar was occasionally missing. These data suggest roles for Nkx2-3 during pharyngeal organogenesis, although the considerable potential for genetic redundancy within and outside of this gene family may mask earlier functions in organ specification.