Altered expression of laminin alpha1 in aganglionic colon of endothelin receptor-B null mouse model of Hirschsprung’s disease

Purpose

Laminin, an extracellular matrix molecule, is essential for normal development of the nervous system. The alpha1 subunit of laminin-1 (LAMA1) has been reported to promote neurites and outgrowth and is expressed only during embryogenesis. Previously, we developed a Sox10 transgenic version of the Endothelin receptor-B (Ednrb) mouse to visualize Enteric neural crest-derived cell (ENCC)s with a green fluorescent protein, Venus. We designed this study to investigate the expression of LAMA1 using Sox10-VENUS mice gut.

Methods

We harvested the gut on days 13.5 (E13.5) and 15.5 (E15.5) of gestation. Sox10-VENUS⁺/Ednrb ^?/? mice (n?=?8) were compared with Sox10-VENUS⁺/Ednrb ^+/+ mice (n?=?8) as controls. Gene expression of LAMA1 was analysed by real-time RT-PCR. Fluorescent immunohistochemistry was performed to assess protein distribution.

Results

The relative mRNA expression levels of LAMA1 were significantly increased in HD in the proximal and distal colon on E15.5 compared to controls (p?<?0.05), whereas there were no significant differences on E13.5. LAMA1 was expressed in the serosa, submucosa and basal lamina in the gut, and was markedly increased in the proximal and distal colon of HD on E15.5.

Conclusions

Altered LAMA1 expression in the aganglionic region may contribute to impaired ENCC migration, resulting in HD. These data could help in understanding the pathophysiologic interactions between LAMA1 and ENCC migration.

     

Cholangitis complicated by infection of a simple hepatic cyst

An 87-year-old man was admitted to our hospital due to fever and elevated liver enzymes. Computed tomography (CT) scan revealed bile duct stones with a dilated biliary system, which confirmed the diagnosis of cholangitis. A 12-cm simple hepatic cyst was also seen in the right liver, which had been detected on CT scan 5 years before, and did not change in size. Fever did not subside even after endoscopic biliary drainage and a repeated CT scan showed an enlarged cyst up to 14 cm, suggesting cyst infection. An enlarged hepatic cyst collapsed after percutaneous transhepatic drainage, along with resolution of fever. Simple hepatic cysts are common and most of them are asymptomatic. Infection of simple hepatic cysts is a rare condition and the major entry route is considered as the biliary tract as communication between the biliary tract and cysts is reportedly observed in those cases. However, in our case, no communication was seen on cholangiogram or cystogram on fluoroscopy and bilirubin level of the cyst aspirate was low. Given the fact that patients with cholangitis are rarely complicated by hepatic cyst infection, other routes of bacterial entry to simple hepatic cysts should also be considered.     

Antihyperglycemic therapies and cardiovascular outcomes in patients with type 2 diabetes mellitus: State of the art and future directions

Type 2 diabetes mellitus is a progressive chronic disease and is an established risk factor for cardiovascular disease. Until recently, the cardiovascular safety and efficacy of antihyperglycemic drugs remained uncertain. However, after the changes in regulatory guidance in 2008, a wealth of data has been generated, expanding the focus of the treatment of diabetes from blood glucose control to the prevention of macro-and microvascular complications and improvement in mortality. This article will review cardiovascular outcome trials of antihyperglycemic agents and provide overview of ongoing trials.     

ABT-737 is a useful component of combinatory chemotherapies for chronic myeloid leukaemias with diverse drug-resistance mechanisms

The effect of ABT-737, a BH3-mimicking inhibitor for anti-apoptotic Bcl-2 and Bcl-X_L, but not Mcl-1, against Bcr-Abl-positive (Bcr-Abl⁺) leukaemic cells was examined. ABT-737 potently induced apoptosis in Bcr-Abl⁺ chronic myeloid leukaemia (CML) cell lines and primary CML samples in vitro and prolonged the survival of mice xenografted with BV173 cells, a CML cell line. Higher expression of anti-apoptotic Bcl-2 proteins reduced cell killing by ABT-737 in each cell line, but there was no correlation between the sensitivities to ABT-737 and the specific expression patterns of Bcl-2 family proteins among cell lines. Thus, the cell killing effect of ABT-737 must be determined not only by the expression patterns of Bcl-2 family proteins but also by other mechanisms, such as high expression of Bcr-Abl, or a drug-efflux pump, in CML cells. ABT-737 augmented the cell killing effect of imatinib in Bcr-Abl⁺ cells with diverse drug-resistance mechanisms unless leukaemic cells harboured imatinib-insensitive Abl kinase domain mutations, such as T315I. The combination of homoharringtonine that reduces Mcl-1 enhanced the killing by ABT-737 strongly in Bcr-Abl⁺ cells even with T315I mutation. These results suggest that ABT-737 is a useful component of chemotherapies for CML with diverse drug-resistance mechanisms.     

Timely interaction between prostaglandin and chemokine signaling is a prerequisite for successful fertilization

Timely interaction between the egg and sperm is required for successful fertilization; however, little is known about the signaling therein. Prostaglandin (PG) E receptor EP2-deficient (Ptger2^−/−) female mice exhibit a severe fertilization defect. We investigated the molecular events leading to this failure. We found increased gene expression for chemokines, such as Ccl2, Ccl7, and Ccl9, in Ptger2^−/− cumulus cells (the somatic cells surrounding the egg) compared with wild-type cells. Furthermore, under physiological conditions, cumulus-derived chemokine signaling was found to have a dual action; CCL7 facilitates sperm migration to the cumulus–egg complex and integrin-mediated cumulus extracellular matrix (ECM) assembly to protect eggs. However, in the absence of PGE₂-EP2 signaling, chronic CCL7 signaling results in excessive integrin engagement to the ECM, making the cumulus ECM resistant to sperm hyaluronidase, thereby preventing sperm penetration. Our findings indicate that PGE₂-EP2 signaling negatively regulates the autocrine action of chemokines and prevents excessive cumulus ECM assembly. This interaction between PG and chemokine signaling is required for successful fertilization.     

Roles for corticotropin-releasing factor receptor type 1 in energy homeostasis in mice

ObjectiveExpression of corticotropin-releasing factor type 1 receptor (CRFR1) has been shown on pancreatic β cells, and its activation potentiates glucose-stimulated insulin secretion (GSIS). However, the roles of CRFR1 in energy metabolism beyond insulin release remain elusive.Materials/MethodsWe characterized the metabolic phenotypes of mice lacking CRFR1 (CRFR1KO mice) under conditions of energy excess.ResultsWhen fed a normal diet, the glucose profile of CRFR1KO mice in response to a glucose tolerance test was similar to that of wild-type (WT) mice, while serum insulin levels were significantly lower in CRFR1KO mice, reflecting high insulin sensitivity in part due to very low glucocorticoid levels. Histology of the pancreas revealed islet hypoplasia in CRFR1KO mice, suggesting a role of CRFR1 in maintaining the β cell mass in a manner similar to incretins. In response to a high-fat diet, CRFR1KO mice showed insulin resistance, but serum insulin levels during glucose challenge remained at a low level, indicating defective GSIS. In addition, CRFR1KO mice showed resistance to diet-induced obesity and hepatic steatosis. Although total food intake was not different between CRFR1KO and WT mice, oxygen consumption was significantly increased in CRFR1KO mice. The increased energy expenditure may explain the lean phenotype of CRFR1KO mice under conditions of energy excess.ConclusionsOur results suggest that CRFR1 plays important roles in whole body energy homeostasis, providing compelling evidence of the close relationship between energy homeostasis and the function of the hypothalamic–pituitary–adrenal axis.     

Three fatal cases of rapidly progressive infective endocarditis caused by Staphylococcus aureus: one case with huge vegetation.

Staphylococcus aureus (S. aureus) infective endocarditis (IE) is a severe disease with a high mortality despite intensive therapy. Three cases of S. aureus IE had a rapidly progressive fatal clinical course despite intensive antimicrobial therapy. One case was methicillin-sensitive S. aureus IE, which formed rapidly growing a huge vegetation on a prosthetic mitral valve, complicated with multiple systemic emboli. The other 2 cases were methicillin-resistant S. aureus IE without any predisposing heart disease.     

Peroxisome proliferator-activated receptor activity is involved in the osteoblastic differentiation regulated by bone morphogenetic proteins and tumor necrosis factor-α

Recent studies have suggested possible adverse effects of thiazolidinediones on bone metabolism. However, the detailed mechanism by which the activity of PPAR affects bone formation has not been elucidated. Impaired osteoblastic function due to cytokines is critical for the progression of inflammatory bone diseases. In the present study, we investigated the cellular mechanism by which PPAR actions interact with osteoblast differentiation regulated by BMP and TNF-α using mouse myoblastic C2C12 cells. BMP-2 and -4 potently induced the expression of various bone differentiation markers including Runx2, osteocalcin, type-1 collagen and alkaline phosphatase (ALP) in C2C12 cells. When administered in combination with a PPARα agonist (fenofibric acid) but not with a PPARγ agonist (pioglitazone), BMP-4 enhanced osteoblast differentiation through the activity of PPARα. The osteoblastic changes induced by BMP-4 were readily suppressed by treatment with TNF-α. Interestingly, the activities of PPARα and PPARγ agonists reversed the suppression by TNF-α of osteoblast differentiation induced by BMP-4. Furthermore, TNF-α-induced phosphorylation of MAPKs, NFκB, IκB and Stat pathways was inhibited in the presence of PPARα and PPARγ agonists with reducing TNF-α receptor expression. In view of the finding that inhibition of SAPK/JNK, Stat and NFκB pathways reversed the TNF-α suppression of osteoblast differentiation, we conclude that these cascades are functionally involved in the actions of PPARs that antagonize TNF-α-induced suppression of osteoblast differentiation. It was further discovered that the PPARα agonist enhanced BMP-4-induced Smad1/5/8 signaling through downregulation of inhibitory Smad6/7 expression, whereas the PPARγ agonist impaired this activity by suppressing BMPRII expression. On the other hand, BMPs increased the expression levels of PPARα and PPARγ in the process of osteoblast differentiation. Thus, PPARα actions promote BMP-induced osteoblast differentiation, while both activities of PPARα and PPARγ suppress TNF-α actions. Collectively, our present data establishes that PPAR activities are functionally involved in modulating the interaction between the BMP system and TNF-α receptor signaling that is crucial for bone metabolism.     

Molecular genotyping of Mycobacterium tuberculosis in Mie Prefecture, Japan, using variable numbers of tandem repeats analysis

The variable numbers of tandem repeats (VNTR) analysis is a method frequently employed as a molecular epidemiological tool for Mycobacterium tuberculosis genetic fingerprinting. In this study, we characterized the population of M. tuberculosis circulating in Mie Prefecture, Japan, and assessed the utility of the proposed JATA12- and 15-VNTR analyses of 158 M. tuberculosis clinical isolates using 25 VNTR loci. The results revealed that the ancient Beijing sublineage is the most prevalent M. tuberculosis strain in Mie Prefecture, accounting for 85.0% of 113 Beijing lineage isolates. Our results also showed that JATA-VNTR using well-selected loci is as reliable as standardized 15-locus MIRU-VNTR. Furthermore, JATA15-VNTR analysis reliably improved the discriminatory power compared with basic JATA12-VNTR analysis. In summary, our data suggest that JATA-VNTR is a useful tool for discrimination of M. tuberculosis in areas where ancient Beijing strains are frequently isolated.