[Medical application of transgenic mice].
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Amyloidosis↗
Biomedical subjects
K Yamamura
Publications and source records attributed to K Yamamura.
Prevention of systemic lupus erythematosus in autoimmune BXSB mice by a transgene encoding I-E alpha chain.
Males from the BXSB murine strain (H-2b) spontaneously develop an autoimmune syndrome with features of systemic lupus erythematosus (SLE), which results in part from the action of a mutant gene (Yaa) located on the Y chromosome. Like other H-2b mice, the BXSB strain does not express the class II major histocompatibility complex antigen, I-E. Here we report that the expression of I-E (E alpha dE beta b) in BXSB males bearing an E alpha d transgene prevents hypergammaglobulinemia, autoantibody production, and subsequent autoimmune glomerulonephritis. These transgenic mice bear on the majority of their B cells not only I-E molecules, but also an I-E alpha chain-derived peptide presented by a higher number of I-Ab molecules, as recognized by the Y-Ae monoclonal antibody. The I-E+ B cells appear less activated in vivo than the I-E- B cells, a minor population. This limited activation of the I-E+ B cells does not reflect a functional deficiency of this cell population, since it can be stimulated to IgM production in vitro by lipopolysaccharides at an even higher level than the I-E- B cell population. The development of the autoimmune syndrome in the transgenic and nontransgenic bone marrow chimeric mice argues against the possibility that the induction of regulatory T cells or clonal deletion of potential autoreactive T cells as a result of I-E expression is a mechanism of the protection conferred by the E alpha d transgene. We propose a novel mechanism by which the E alpha d transgene protects BXSB mice against SLE: overexpression of I-E alpha chains results in the generation of excessive amounts of a peptide displaying a high affinity to the I-Ab molecule, thereby competing with pathogenic autoantigen-derived peptides for presentation by B lymphocytes and preventing their excessive stimulation.
Animals↗
Multimeric forms of Tyr-Ile-Gly-Ser-Arg (YIGSR) peptide enhance the inhibition of tumor growth and metastasis.
The Tyr-Ile-Gly-Ser-Arg (YIGSR) peptide derived from the laminin B1 chain has been shown to decrease tumor growth and metastasis. Utilizing the multimeric antigen peptide system assembled on a branched lysine core, we synthesized several sizes of multimeric YIGSR, (CH3CO-Tyr-Ile-Gly-Ser-Arg-Gly)16-Lys8-Lys4-Lys2 -Lys-Gly [(Ac-YIGSRG)16 K8K4K2KG] (designated Ac-Y16), (Ac-YIGSRG)8K4K2KG (Ac-Y8), and (Ac-YIGSRG)4K2KG (Ac-Y4), and related peptides, Ac-(YIGSRG)4-NH2 (Ac-Y4L) and Ac-YIGSR-NH2 (Ac-Y1) and evaluated their biological activities in inhibiting tumor growth and metastasis. Coinjection of 0.2 mg/mouse of Ac-Y16 i.v. with B16-F10 mouse melanoma cells inhibited lung colony formation by 97%, whereas 0.2 mg/mouse of Ac-Y1 inhibited by 50%. The larger the peptide (Ac-Y16 > Ac-Y8 > Ac-Y4 > Ac-Y1), the more inhibitory effect there was on lung metastasis. Ac-Y16 also inhibited the growth of s.c.-injected B16-F10 tumors. These data demonstrate that the multimeric YIGSR peptides strongly enhanced the activity of YIGSR in inhibiting tumor growth and metastasis and suggest that these compounds are potentially useful for clinical applications.
Amino Acid Sequence↗
Osteoarthritis associated with mild chondrodysplasia in transgenic mice expressing alpha 1(IX) collagen chains with a central deletion.
Type IX collagen, containing molecules of the three distinct polypeptides alpha 1(IX), alpha 2(IX), and alpha 3(IX), is an interesting hybrid extracellular matrix component in cartilage and eye tissues, with the properties of both a proteoglycan and a collagen. The alpha 1 (IX) chain has two forms, as a result of the tissue-specific utilization of two alternative promoters; the alpha 2(IX) chain carries a covalently attached glycosaminoglycan side chain. We have introduced a gene construct controlled by a tissue-specific promoter/enhancer and expressing a truncated alpha 1(IX) chain into mice. Examination of the offspring of two different founders revealed pathological changes similar to osteoarthritis in the articular cartilage of knee joints. In addition, mice homozygous for the transgene developed mild chondrodysplasia (i.e., mild dwarfism, anterior tonguing in the vertebral bodies, and ophthalmopathy). The relative ratio of transgene product to the endogenous alpha 1(IX) chain was approximately one in homozygotes and less than one in heterozygotes. Therefore, the phenotypic severity correlated well with the level of transgene expression. These findings suggest that mutations in type IX collagen genes may cause certain forms of osteoarthritis and chondrodysplasia in humans.
Animals↗
Melanoma cells selected for adhesion to laminin peptides have different malignant properties.
Laminin is an important promoter of cell-matrix interactions. A number of active laminin domains have been defined by use of synthetic peptides. The Tyr-Ile-Gly-Ser-Arg (YIGSR) sequence on the B1 chain in laminin can decrease tumor growth and metastasis, whereas another sequence containing Ser-Ile-Lys-Val-Ala-Val (SIKVAV) on the A chain can increase tumor growth and metastasis. Here, we selected B16-F10 melanoma cells by adherence or nonadherence to either YIGSR- or SIKVAV-coated dishes and established 3 B16-F10 variants: YIGSR-adherent cells (Y+), YIGSR-nonadherent cells (Y-), and SIKVAV-nonadherent cells (S-). SIKVAV-adherent cells were not selected because most of F10 cells attached to the SIKVAV-coated dish. These cell lines proliferated at the same rate as the parent F10 cells and attached equally to laminin, collagen IV, and fibronectin. Y+ cells produced rapidly growing tumors after s.c. injection and twice as many lung colonies as the parental F10 cells after i.v. injection. In contrast, Y- cells produced more slowly growing tumors after s.c. injection and produced one-third of the lung colonies relative to the parent cells after i.v. injection. S- cells produced slowly growing tumors after s.c. injection and yielded similar numbers but smaller colonies in the lung than the parental B16-F10 cells after i.v. injection. These data suggest that interactions of melanoma cells with the YIGSR site on laminin are probably important for both colony formation in a target organ (lung) and subsequent tumor growth, while the SIKVAV-containing site on laminin may be more important for tumor growth.
Amino Acid Sequence↗
[Experimental study on reversibility of neuronal function in rats with congenital hydrocephalus].
To evaluate the usefulness of cerebral evoked potential examination in determining the severity of hydrocephalus and its prognosis, we measured brainstem auditory evoked potential (BAEP), somatosensory evoked potential (SEP), and visual evoked potential (VEP) in rats with HTX congenital hydrocephalus. In addition, changes in cerebral evoked potentials were measured before and after shunt operation, and the reversibility of neuronal function was evaluated. In control rats without hydrocephalus, SEP appeared in the latter half of the first week after birth, and VEP and BAEP in the former half of the second week. The peak latency tended to gradually decrease with growth. Significant differences were observed in SEP in the latter half of the second week after birth and in VEP in the former half of the third week between the group with hydrocephalus and the control group. However, BAEP did not significantly differ between the two groups. These results suggest that impairment of cerebral function is more marked than that of brainstem function in rats with HTX congenital hydrocephalus, and SEP is the most useful for evaluating the progression of this disease. Ventriculo-peritoneal shunt was performed in the rats with hydrocephalus in the latter half of the second week, when the N1 latency of SEP began to be prolonged, or in the latter half of the third week. Outcomes markedly differed between the two groups. However, the N1 latency of postoperative SEP was shortened in both groups. These results strongly suggest that the reversibility of neuronal function in hydrocephalus evaluated by SEP examination is well preserved until the terminal stage. Cerebral evoked potential examination, especially, SEP examination may be useful for evaluating the degree of impairment in neuronal function in hydrocephalus.
Animals↗
Transgenic mouse model for human genetic diseases.
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Age Factors↗
The effects of low-frequency ultrasound on the inner ear: an electrophysiological study using the guinea pig cochlea.
By examining 218 albino guinea pigs, electrophysiological methods were used to investigate the effects of low frequency ultrasound at moderate sound pressure levels after long-term exposure to the inner ear. From 10 kHz to 28 kHz, low frequency ultrasound below 100 dB SPL induced significant changes in cochlear microphonics, elevated thresholds and decreased maximum output voltage of action potentials and decreased absolute values of negative potentials of the endocochlear potentials.
Acoustic Stimulation↗
The laminins: a family of basement membrane glycoproteins important in cell differentiation and tumor metastases.
Laminins are a family of basement membrane-derived glycoproteins that are very biologically active with a number of diverse cell types. The response of the cells is dependent on the cell type and various cell-specific intracellular events are activated. Multiple active sites on laminin and cellular receptors have been described. Both laminin and the synthetic peptides that define the active sites may have important clinical uses. For example, the neurite-promoting peptides may be useful in vivo in regeneration studies because of their potent activity with neural cells and their lack of antigenicity. Also, peptides, such as YIGSR, that inhibit angiogenesis are potentially useful for treating the vascularization of the eye that occurs in conditions such as diabetes mellitus. Likewise, the angiogenic peptide SIKVAV, because of its role in endothelial cell block vessel formation, may be useful for treating ischemia. The recent progress that has been made in characterizing basic mechanisms of action of laminin has laid the groundwork for more direct studies of its clinical relevance.
Amino Acid Sequence↗
Transgenic mouse lines with ectopic expression of alpha-1,3-galactosyltransferase: production and characteristics.
The cDNA of murine alpha-1,3-galactosyltransferase was placed under the control of the beta-actin promoter and cytomegalovirus enhancer, then introduced into male pronuclei of fertilized mouse eggs. The three transgenic mouse lines obtained were analysed for the expression of the transferase by staining with Griffonia simplicifolia agglutinin I-B4 (GSI-B4), which is alpha-galactosyl specific. Compared with wild-type mice, all lines of transgenic mice expressed GSI-B4 binding sites more intensely in the renal tubular brush border and lung alveolar epithelium, and newly expressed them in the photoreceptor outer segments, goblet cells of the small intestine and around spermatogonia. GSI-B4 binding sites were also detected in the liver of some transgenic mice. Even though the introduced enzyme gene was expressed in embryos, it did not severely hinder embryogenesis. The transgenic mice tended to secrete more proteins in the urine than the wild type. Furthermore, low body weights, partial damage to hair growth and early death occurred more frequently in the transgenic mice.
Animals↗
The role of macrophages in antigen presentation and T cell tolerance.
Bone marrow derived cells (dendritic cells, macrophages and B cells) are involved in antigen presentation and T cell tolerance. However, the precise functions of each cell type remain unclear. To determine the role of macrophages we produced transgenic mice expressing I-E molecules only on macrophages, by introducing the hybrid gene containing the colony stimulating factor-1 (CSF-1) receptor promoter region and the structural gene encoding E alpha d into C57BL/6 mice. In these mice I-E restricted antigen presentation and T cell priming were impaired. With respect to T cell tolerance, I-E reactive T cells were anergized but not clonally deleted. These results clearly demonstrate that macrophages by themselves are defective in efficient I-E restricted antigen presentation, so that T cells exposed to antigens expressed on macrophages are led to anergy.
Animals↗
An efficient gene-trap method using poly A trap vectors and characterization of gene-trap events.
New trap vectors (U1 and U2) have been developed to trap genes in murine embryonic stem (ES) cells. The polyA addition signal of the neomycin phosphotransferase II (neo) gene was removed from these vectors so that they needed to trap an endogenous polyA signal for expression of the neo gene. The frequency of gene-trap events of these vectors was about five times higher than with the vector containing the polyA signal, and only one copy of the trap vector was integrated in most cases. Four out of five 5'-flanking regions of the integrated vector in ES cell lines were found to be novel endogenous promoters, suggesting that this method is efficient for trapping genes in ES cells. In two cases analyzed, large deletions or rearrangements spanning more than 10 kb were found in the 3'-flanking region of the trap vector introduced by electroporation. This result suggests that phenotypes observed in homozygotes with a mutated allele could be due to the disruption of a gene adjacent to the trapped gene, but not of the trapped gene.
Animals↗
Relation between glucose-stimulated insulin secretion and intracellular calcium accumulation studied with a superfusion system of a glucose-responsive pancreatic beta-cell line MIN6.
The concept that cytosolic free calcium is the primary signal for insulin secretion is generally accepted, but studies with intact pancreatic beta-cells of the cytosolic free calcium concentration-insulin secretion relationship have produced contradictory and sometimes confusing data. We designed a superfusion system of a pancreatic beta-cell line, MIN6, loaded with fura-2, which allowed simultaneous measurement of cytosolic free calcium concentration and insulin secretion. MIN6 cells released insulin in response to high glucose, thus resembling events in normal islet cells. Cytosolic free calcium concentration and insulin secretion rapidly increased, and the increase was suppressed by mannoheptulose or by sodium azide. This increase was suppressed by lowering the temperature of the medium. Cytosolic free calcium concentration and the insulin secretion induced by leucine were not influenced by mannoheptulose but were inhibited by sodium azide. In RINm5F cells, cytosolic free calcium concentration and insulin release were slightly suppressed by glucose but were increased by ionomycin. There was a close relation between the rise in cytosolic free calcium concentration and insulin secretion in all cases. Our findings provide a direct evidence that a rise in cytosolic free calcium concentration depends on glucose metabolism and is a primary signal for insulin secretion.
Animals↗
Effect of Matrigel and laminin peptide YIGSR on tumor growth and metastasis.
Basement membrane has a variety of effects on tumor cells and promotes malignant behavior. Tumor cell growth is enhanced both in vitro and in vivo in mice in the presence of basement membrane. This has led to the ability to grow various tumors including human biopsy specimens in nude mice. Furthermore, low cell numbers can be used when coinjected with Matrigel, a basement membrane extract. The basement membrane glycoprotein laminin is important in promoting invasive behavior and the level of a 32/67 kDa laminin receptor has been shown to correlate with malignancy. A sequence of five amino acids, tyrosine-isoleucine-glycine-serine-arginine (YIGSR) has been shown to recognize this receptor and to reduce experimental metastases (tail vein injection resulting in colonization of the lung) and subcutaneous tumor growth. This peptide is active in both models either when coinjected or when daily intraperitoneal injections are given after tumor growth has initiated. YIGSR does not effect cell arrest but does inhibit angiogenesis which is necessary for tumor growth. YIGSR also appears to have an additional antitumor effect via its interaction with a specific receptor. YIGSR-adherent cells established after 30 successive selections on YIGSR-coated dishes in vitro formed more lung colonies after intravenous injection and larger tumors after subcutaneous injection than the parent B16F10 melanoma cells. The YIGSR-non-adherent cells formed fewer lung colonies and smaller subcutaneous tumors. These data demonstrate the importance of laminin-tumor cell interactions in malignancies and suggest that a short sequence from laminin has multiple effects in reducing tumor growth and spread.(ABSTRACT TRUNCATED AT 250 WORDS)
Amino Acid Sequence↗
[Falx metastasis of thymic carcinoma: a case report and review of literature].
A patient, a 72-year-old male, with a thymic carcinoma spreading to the extrathoracic region, is reported. he had undergone a thoracotomy and received radiation-and chemotherapy. Four months later, the patient was noticed to have a mild left sided hemiparesis. Further evaluations revealed metastasis of thymic carcinoma to the bone and intracranial region. Surgical treatment for intracranial lesion was performed, and the patient's left sided hemiparesis was cleared. Thymic carcinoma is uncommon, and its intracranial metastasis is rare. We found 27 previous reports of intracranial metastasis of thymic carcinoma and malignant thymoma. This time, we report a case of thymic carcinoma with intracranial (falx) metastasis, and discuss the concept of thymic carcinoma and thymomas in a review of the literature.
Aged↗
Low responsiveness of hepatitis B virus-transgenic mice in antibody response to T-cell-dependent antigen: defect in antigen-presenting activity of dendritic cells.
The experiments presented here were performed to evaluate immune responsiveness of hepatitis B virus (HBV)-transgenic mice (transgenic mice), as a model of HBV-carrier state to a T-cell-dependent antigen, keyhole limpet haemocyanin (KLH). The transgenic mice which were completely unresponsive to hepatitis B surface antigen (HBsAg), responded poorly to KLH. The levels of anti-KLH antibodies (Ab) produced in vivo were significantly lower in transgenic mice compared with the normal control mice at respective immunizing doses of KLH. In addition, a little or no anti-KLH Ab production was detected in culture supernatants of KLH-primed transgenic mice spleen cells. KLH-primed T cells from normal and transgenic mice induced anti-KLH Ab production from transgenic B cells in the presence of antigen-presenting spleen adherent cells (SAC) from normal mice, but not those from transgenic mice. Depletion of dendritic cells from normal mice-derived SAC completely abrogated the anti-KLH Ab response in transgenic spleen cell culture and their addition to the culture restored the response. Low efficiency of transgenic dendritic cells was demonstrated in sodium periodate (NaIO4)-induced non-specific and allogenic antigen-induced T-cell proliferation. Finally, cytofluorometric analyses showed a reduced Ia antigen expression on transgenic dendritic cells. These results indicate that low responsiveness of transgenic mice in specific-antibody response is not due to functional defects in T cells or B cells but rather to a defect of antigen-presenting activity of dendritic cells.
Animals↗
Prevention of autoimmune insulitis in nonobese diabetic mice by expression of major histocompatibility complex class I Ld molecules.
Nonobese diabetic (NOD) mice spontaneously develop a T-cell-mediated autoimmune disease that is similar in many respects to insulin-dependent diabetes mellitus in humans. NOD mice were shown to express major histocompatibility complex class I Kd and Db antigens. To examine the possible involvement of major histocompatibility complex class I molecules in the development of autoimmune insulitis, we attempted to express a different type of class I molecule in NOD mice by crossing C57BL/6 mice transgenic for the class I Ld gene with NOD mice. The backcross progeny expressed the Ld antigen on the peripheral blood lymphocytes at a level comparable with that of the BALB/c mice. The cell surface expression of endogenous class I and class II antigens on the peripheral blood lymphocytes was not affected. Analysis of these mice revealed that the expression of the class I Ld antigen significantly reduced the incidence of insulitis at 20 weeks of age. In situ hybridization of a biotinylated probe on mouse chromosomes showed that the Ld transgene was located in the E area of chromosome 6 with which no genetic linkage to insulin-dependent diabetes mellitus was demonstrated. These results suggest that the NOD-type class I molecules are involved in the development of insulitis in NOD mice.
Animals↗
Generation of plasmacytomas with the chromosomal translocation t(12;15) in interleukin 6 transgenic mice.
The mechanisms through which pristane or mineral oil can induce plasmacytomas in BALB/c or NZB mice are not fully understood, but involvement of interleukin 6 (IL-6), a growth factor for plasmacytomas and myelomas, has been strongly suggested. To clarify the role of IL-6 in plasmacytomagenesis, a human IL-6 cDNA was introduced into mouse germ lines under the transcriptional control of the murine major histocompatibility complex class I (H-2Ld) promoter. IL-6 transgenic mice of C57BL/6 origin developed a massive plasmacytosis but not plasmacytomas. However, introduction of BALB/c genetic background into IL-6 transgenic mice could generate monoclonal transplantable plasmacytomas with the chromosomal translocation t(12;15). These results provide firm evidence of the critical role of IL-6 in the plasmacytoma development.
Animals↗