Primrose syndrome associated with unclassified immunodeficiency and a novel ZBTB20 mutation

Primrose syndrome is a congenital malformation syndrome characterized by intellectual disability, developmental delay, progressive muscle wasting, and ear lobe calcification. Mutations in the ZBTB20 gene have been established as being accountable for this syndrome. In this study, a novel de novo ZBTB20 mutation, NM_001164342.2:c.1945C>T (p.Leu649Phe), has been identified through whole exome sequencing (WES) in a female patient presenting a typical Primrose phenotype. Because the present patient exhibited recurrent otitis media, detailed immunological examinations were performed in this study and subnormal immunoglobulin levels were firstly identified in a Primrose patient. Anatomical anomaly of the inner ear has never been reported in this patient and WES data did not include any relevant variants causally linked with the immunologic defect. Thus, there is a possibility of a relation between an unclassified immunodeficiency with selective IgG2 deficiency and Primrose syndrome and this may be the reason of recurrent otitis media frequently observed in Primrose patients. Because subnormal levels of IgG2 in this patient might be caused by an unrelated and still uncharacterized genetic cause, further studies are required to prove the causal link between aberrant ZBTB20 function and immunodeficiency.     

Glomerular expression of cell-cycle-regulatory proteins in human crescentic glomerulonephritis

To elucidate the mechanism underlying crescentic formation, we assessed the phenotypic characterization and cell-cycle protein expression in human crescentic glomerulonephritis (CRGN). Kidney tissue specimens taken from CRGN patients (10 patients with pauci-immune type rapidly progressive glomerulonephritis (RPGN), 2 patients with Henoch-Schönlein purpura nephritis, and 1 patient with IgA nephropathy) were examined immunohistochemically. Most of the cellular components of the crescents expressed cytokeratin, whereas few cells expressed PHM-5. CD68-positive cells were minor components of cellular crescents, indicating that the major principal cellular component of the crescents is made up of cells with the parietal glomerular epithelial cell (PEC) phenotype. Additionally, serial section analysis revealed that Ki-67-positive cells in the crescents were frequently cyclin-A positive and Bcl-2 positive, but seldom cyclin-B₁ positive. Moreover, the expression of cyclin-dependent kinase inhibitor p27^Kip1 was low in the cellular crescents, despite being exclusively positive in podocytes within the same section. We concluded that the major component of the cellular crescents is made up of PECs and that apparent expression of cyclins and Bcl-2 and restrained expression of p27^Kip1 may be synergistically associated with the development of cellular crescents in human CRGN.     

An invasion-independent pathway of blood-borne metastasis: a new murine mammary tumor model

It is generally believed that active invasion by cancer cells is essential to the metastatic process. In this report, we describe a murine mammary tumor (MCH66) model of metastasis that does not require invasion into the vascular wall of both the primary tumor and the target organ, in this case, the lung. The process involves intravasation of tumor nests surrounded by sinusoidal blood vessels, followed by intravascular tumor growth in the lung, without penetration of the vascular wall during the process. Comparative studies using a nonmetastatic MCH66 clone (MCH66C8) and another highly invasive metastatic cell line (MCH416) suggested that high angiogenic activity and sinusoidal remodeling of tumor blood vessels were prerequisites for MCH66 metastasis. Differential cDNA analysis identified several genes that were overexpressed by MCH66, including genes for the angiogenesis factor pleiotrophin, and extracellular matrix-associated molecules that may modulate the microenvironment toward neovascularization. Our analyses suggest that tumor angiogenesis plays a role in the induction of invasion-independent metastasis. This model should prove useful in screening and development of new therapeutic agents for cancer metastasis.     

Induction of Thymus-Derived γδ T Cells by Escherichia coli Enterotoxin B Subunit in Peritoneal Cavities of Mice

We examined the activation of intraperitoneal T cells in BALB/c mice by the Escherichia coli enterotoxin B subunit, which induced a specific Th2 type of T-cell response to intraperitoneally coadministered bovine immunoglobulin G. The numbers of both γδ and αβ T cells increased significantly after intraperitoneal administration of the B subunit in a time-dependent manner; these numbers were not affected by the B-subunit G33D mutant, which is defective in GM₁ ganglioside-binding ability. Early after administration a small number of γδ T cells produced either interleukin-4 (IL-4) or gamma interferon, while late after administration primarily IL-10-producing γδ T cells were detected. γδ T cells induced by the B subunit did not express a characteristic V gene over the time course of the study. The induction of γδ T cells did not occur in athymic nu/nu mice but could be induced upon transplantation of fetal AKR thymus-like αβ T cells. γδ T cells in athymic nu/nu mice with a fetal thymic graft predominantly expressed the donor Thy-1.1 antigen but not the host Thy-1.2 antigen. The induction of these T cells, however, could not be restored by coadministration of the B subunit with peritoneal cells from normal mice. These results suggest that the B subunit activates intraperitoneal γδ and αβ T cells in a manner dependent upon its ability to bind to GM₁ ganglioside. γδ T cells induced by the B subunit are Th2-type cells derived from the thymus. These γδ T cells may be functionally involved in specific Th2 responses to the B subunit, which possibly acts as an adjuvant through the influence of αβ T cells.     

Cell Cycle Regulation and Differentiation in the Human Podocyte Lineage

Mature podocytes are regarded as growth-arrested cells with characteristic phenotypic features that underlie their function. To determine the relationship between cell cycle regulation and differentiation, the spatiotemporal expression of cyclin A, cyclin B1, cyclin D1, the cyclin-dependent kinase inhibitors (CKIs) p27 and p57, and markers of differentiating podocytes in developing human kidneys was investigated by immunohistochemistry. In S-shaped body stage, Ki-67, a cell proliferation marker that labels the G1/S/G2/M phase, was expressed in the majority (more than 80%) of presumptive podocytes, along with cyclin A (~20% of the Ki-67-positive cells) and cyclin B1 (less than 5% of Ki-67-positive cells) expression. Among these cells, cyclin D1 and CKIs were markedly down-regulated. At the capillary-loop stage, by contrast, CKIs and cyclin D1 were intensely positive in podocytes, whereas no Ki-67, cyclin B1, or cyclin A expression was seen. Moreover, double-immunolabeling and serial-section analysis provided evidence that CKIs and markers specific for differentiating podocytes, namely PHM-5 (podocalyxin-like protein in humans), synaptopodin (a foot process-related protein), and C3b receptor, were co-expressed at the capillary-loop stage. Podocytes were the only cells within the glomeruli that expressed CKIs at immunohistochemically detectable levels. Furthermore, bcl-2 (an apoptosis inhibitory protein) showed a reciprocal expression pattern to that of CKI. These results suggest that 1) the cell cycle of podocytes is regulated by cyclin and CKIs, 2) CKIs may act to arrest the cell cycle in podocytes at the capillary-loop stage, and 3) the specific cell cycle system in podocytes may be closely correlated with their terminal differentiation in humans.     

Clinicopathologic features and incidence of invasive lobular carcinoma in Japanese women

Intending to clarify the true Incidence of Invasive lobular carcinoma of the breast In Japanese women as well as the frequency of unilateral multlcentriclty, 362 cases of clinically defined monocentrlc breast cancer without pre-operative biopsy (previously fine needle aspiration or needle biopsy were routinely carried out for every case) were examined by whole mammary gland serial sectioning. On the basis of pathology and the World Health Organization classification of breast tumors, each case was assigned to one of two main histologlc types: Invasive lobular carcinoma (ILC) or Invasive ductal carcinoma (IDC). Invasive lobular carcinoma was further separated into classic and variant types by employing previously published criteria. Twenty-one cases of ILC (5.8%) were diagnosed, which Is more than In most previous Japanese studies. Unilateral multicentric breast carcinoma was detected In 9.5% of ILC and 16.1% of IDC (the difference was found not significant). Microscopically, ILC tumors were found to be, on average, larger than IDC. Patients with classic type ILC tended to be younger than those with variant type or IDC. Estrogen receptor expression was found more frequently In variant type ILC than in classic type. These results suggest that the incidence of invasive lobular carcinoma of the breast In Japanese women is low and that unilateral multicentricity Is not significantly higher in ILC than in IDC.     

Mutation analysis of HNF-4 binding sites in the human glucose-6-phosphatase promoter

HNF-4, a member of the nuclear receptor superfamily, binds to HNF-4 response elements (HRE), consisting of a direct repeat of the hexameric half-sites spaced by 1 nt (direct repeat 1) and activates a number of genes, which play central roles in fatty acids and glucose metabolism. Glucose-6-phosphatase (G6Pase) catalyzes the terminal step in the gluconeogenic and glycogenolytic pathways. A previous study has shown that HNF-4 binds to two DR1s in the regions A (located between -266 and -234) and B (located between -306 and -274) on the human G6Pase promoter. We found that the region B contains the one more DR1 element, composed of the two half-sites, designated half-sites a and b, the latter of which overlaps with the previously identified DR1 consisting of two half-sites, designated half-sites b and c. In this study, electrophoretic mobility shift assay (EMSA) using point mutations in each half-site a, b, or c indicated that HNF-4 binds to the combination of half-sites a and b, but not to half-sites b and c. Furthermore, mutational analysis demonstrated that, in the context of the human G6Pase promoter, the half-sites a and b, but not the half-sites b and c, are required for the stimulatory effect of HNF-4. These results suggested that the DR1 element containing the half-sites a and b is a functional HRE that mediates the induction of hG6Pase promoter activity by HNF-4.     

The course ofAngiostrongylus cantonensis infection in athymic nude and neonatally thymectomized mice

BALB/c athymic nude and thymus-reconstituted nude mice and neonatally thymectomized BALB/c mice were infected with stage 3 larvae ofAngiostrongylus cantonensis and the worm burdens of the mice were determined at various times after infection. When the nude and thymectomized mice were exposed to the parasite, some worms were found to migrate from the brain to lungs but died there without reaching maturity. This pulmonary arterial migration of the worms in the nude mice did not occur following thymic reconstitution. These data suggest that the inability of murine intracranial worms to migrate to the lungs is at least in part due to thymus-dependent mechanisms, and also that the failure of worm maturation in mouse lungs might be due to thymus-independent immune mechanisms and/or nonimmunological mechanisms.