Constitutively active parathyroid hormone receptor signaling in cells in osteoblastic lineage suppresses mechanical unloading-induced bone resorption

Multiple signaling pathways participate in the regulation of bone remodeling, and pathological negative balance in the regulation results in osteoporosis. However, interactions of signaling pathways that act comprehensively in concert to maintain bone mass are not fully understood. We investigated roles of parathyroid hormone receptor (PTH/PTHrP receptor) signaling in osteoblasts in unloading-induced bone loss using transgenic mice. Hind limb unloading by tail suspension reduced bone mass in wild-type mice. In contrast, signaling by constitutively active PTH/PTHrP receptor (caPPR), whose expression was regulated by the osteoblast-specific Col1a1 promoter (Col1a1-caPPR), suppressed unloading-induced reduction in bone mass in these transgenic mice. In Col1a1-caPPR transgenic (Tg) mice, hind limb unloading suppressed bone formation parameters in vivo and mineralized nodule formation in vitro similarly to those observed in wild-type mice. In addition, serum osteocalcin levels and mRNA expression levels of type I collagen, Runx2 and Osterix in bone were suppressed by unloading in both wild-type mice and Tg mice. However, in contrast to unloading-induced enhancement of bone resorption parameters in wild-type mice, Col1a1-caPPR signaling suppressed, rather than enhanced, osteoclast number and osteoclast surface as well as urinary deoxypyridinoline excretion upon unloading. Col1a1-caPPR signaling also suppressed mRNA expression levels of RANK and c-fms in bone upon unloading. Although the M-CSF and monocyte chemoattractant protein 1 (MCP-1) mRNA levels were enhanced in control Tg mice, these levels were suppressed in unloaded Tg mice. These results indicated that constitutive activation of PTH/PTHrP receptor signaling in osteoblastic cells suppresses unloading-induced bone loss specifically through the regulation of osteoclastic activity.     

Role of PKC and TGF-beta receptor in glucose-induced proliferation of smooth muscle cells

The role of protein kinase C (PKC) and transforming growth factor (TGF)-beta in the proliferation of vascular smooth muscle cells (SMCs) under a high glucose condition was investigated. [3H]-thymidine incorporation under 20 mM glucose was significantly accelerated compared with that under 5.5 mM glucose, and this increase was inhibited by an anti-TGF-beta antibody or a PKC-beta specific inhibitor, LY333531. The amount of active and total TGF-beta1 in the conditioned media did not differ between 5.5 and 20 mM glucose. However, the expression of TGF-beta receptor type II under 20 mM glucose was significantly increased, but that of the TGF-beta receptor type I was not. This increased expression of the TGF-beta receptor type II was prevented by LY333531. These observations suggest that the increased expression of the TGF-beta receptor type II via PKC-beta plays an important role in the accelerated proliferation of SMCs under a high glucose condition, leading to the development of diabetic macroangiopathy.     

Akhirin regulates the proliferation and differentiation of neural stem cells in intact and injured mouse spinal cord

Although the central nervous system is considered a comparatively static tissue with limited cell turnover, cells with stem cell properties have been isolated from most neural tissues. The spinal cord ependymal cells show neural stem cell potential in vitro and in vivo in injured spinal cord. However, very little is known regarding the ependymal niche in the mouse spinal cord. We previously reported that a secreted factor, chick Akhirin, is expressed in the ciliary marginal zone of the eye, where it works as a heterophilic cell‐adhesion molecule. Here, we describe a new crucial function for mouse Akhirin (M‐AKH) in regulating the proliferation and differentiation of progenitors in the mouse spinal cord. During embryonic spinal cord development, M‐AKH is transiently expressed in the central canal ependymal cells, which possess latent neural stem cell properties. Targeted inactivation of the AKH gene in mice causes a reduction in the size of the spinal cord and decreases BrdU incorporation in the spinal cord. Remarkably, the expression patterns of ependymal niche molecules in AKH knockout (AKH?/?) mice are different from those of AKH+/+, both in vitro and in vivo. Furthermore, we provide evidence that AKH expression in the central canal is rapidly upregulated in the injured spinal cord. Taken together, these results indicate that M‐AKH plays a crucial role in mouse spinal cord formation by regulating the ependymal niche in the central canal. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 75: 494–504, 2015     

Temperature seasonality during fry out‐migration influences the survival of hatchery‐reared chum salmon Oncorhynchus keta

Among years, fry‐to‐adult survival of hatchery‐reared chum salmon Oncorhynchus keta was positively correlated with the length (in days) of the fry out‐migration period with temperatures suitable for migration. Furthermore, survival decreased with increasing difference in mean temperature between May and June. Thus, prolonged out‐migration periods increased the probability of survival from fry to adult, lending support to the hypothesis that long migration periods decrease the risk of mortality (bet‐hedging), and increase the probability of migration when environmental conditions in fresh water and the ocean are suitable (match–mismatch).     

Induction of CD44 Variant 9-Expressing Cancer Stem Cells Might Attenuate the Efficacy of Chemoradioselection and Worsens the Prognosis of Patients with Advanced Head and Neck Cancer

Background

At our institute, a chemoradioselection strategy has been used to select patients for organ preservation on the basis of response to an initial 30–40 Gy concurrent chemoradiotherapy (CCRT). Patients with a favorable response (i.e., chemoradioselected; CRS) have demonstrated better outcomes than those with an unfavorable response (i.e., nonchemoradioselected; N-CRS). Successful targeting of molecules that attenuate the efficacy of chmoradioselection may improve results. Thus, the aim of this study was to evaluate the association of a novel cancer stem cell (CSC) marker, CD44 variant 9 (CD44v9), with cellular refractoriness to chemoradioselection in advanced head and neck squamous cell carcinoma (HNSCC).

Materials and Methods

Through a medical chart search, 102 patients with advanced HNSCC treated with chemoradioselection from 1997 to 2008 were enrolled. According to our algorithm, 30 patients were CRC following induction CCRT and 72 patients were N-CRS. Using the conventional immunohistochemical technique, biopsy specimens and surgically removed tumor specimens were immunostained with the anti-CD44v9 specific antibodies.

Results

The intrinsic expression levels of CD44v9 in the biopsy specimens did not correlate with the chemoradioselection and patient survival. However, in N-CRS patients, the CD44v9-positive group demonstrated significantly (P = 0.008) worse prognosis, than the CD44v9-negative group. Multivariate analyses demonstrated that among four candidate factors (T, N, response to CCRT, and CD44v9), CD44v9 positivity (HR: 3.145, 95% CI: 1.235–8.008, P = 0.0163) was significantly correlated with the poor prognosis, along with advanced N stage (HR: 3.525, 95% CI: 1.054–9.060, P = 0.0228). Furthermore, the survival rate of the CD44v9-induced group was significantly (P = 0.04) worse than the CD44v9-non-induced group.

Conclusions

CCRT-induced CD44v9-expressing CSCs appear to be a major hurdle to chemoradioselection. CD44v9-targeting seems to be a promising strategy to enhance the efficacy of chemoradioselection and consequent organ preservation and survival.     

Imatinib mesylate (STI-571) attenuates liver fibrosis development in rats

It is widely recognized that activated hepatic stellate cells (HSC) play a pivotal role in development of liver fibrosis. A platelet-derived growth factor (PDGF) is the most potent mitogen for HSC. The aim of this study was to examine the effect of imatinib mesylate (STI-571, Gleevec), a clinically used PDGF receptor (PDGFR) tyrosine kinase inhibitor, on development of experimental liver fibrosis. The rat model of pig serum-induced hepatic fibrosis was used to assess the effect of daily oral administration of STI-571 on the indexes of fibrosis. STI-571 markedly attenuated development of liver fibrosis and hepatic hydroxyproline and serum fibrosis markers. The number of alpha-smooth muscle actin-positive cells and mRNA expression of alpha2-(I)-procollagen, tissue inhibitor of metalloproteinases-1, and transforming growth factor-beta were also significantly suppressed by STI-571. Our in vitro study showed that STI-571 markedly attenuated PDGF-BB-induced proliferation and migration and alpha-SMA and alpha2-(I)-procollagen mRNA of activated HSC in a dose-dependent manner. STI-571 also significantly attenuated PDGF-BB-induced phosphorylation of PDGFR-beta, MEK1/2, and Akt in activated HSC. Because STI-571 is widely used in clinical practice, it may provide an effective new strategy for antifibrosis therapy.     

Inhibition of Influenza Virus Replication by Phosphorothioate and Liposomally Endocapsulated Oligonucleotides

Abstract

We have demonstrated that antisense phosphorothioate oligonucleotides (S-ODNs) inhibit influenza virus A replication in MDCK cells. Phosphorothioate and liposomally encapsulated oligonucleotides with two target sites (PB1 and PB2) were synthesized and tested for virus-induced cytopathogenicity effects by a MTT assay using MDCK cells. The liposomally encapsulated S-ODNs complementary to the sites of the PB2-AUG initiation codon showed highly inhibitory effects. On the other hand, the inhibitory effect of the liposomally encapsulated S-ODNs targeted to PB1 was considerably decreased in comparison with the PB2 target sites. The liposomally encapsulated oligonucleotides exhibited higher inhibitory activity than the free oligonucleotides. The activities of the modified oligonucleotides are effectively enhanced by using the liposomal carrier.