Synaptic-like microvesicles, synaptic vesicle counterparts in endocrine cells, are involved in a novel regulatory mechanism for the synthesis and secretion of hormones

Microvesicles in endocrine cells are the morphological and functional equivalent of neuronal synaptic vesicles. Microvesicles accumulate various neurotransmitters through a transmitter-specific vesicular transporter energized by vacuolar H+-ATPase. We found that mammalian pinealocytes, endocrine cells that synthesize and secrete melatonin, accumulate L-glutamate in their microvesicles and secrete it through exocytosis. Pinealocytes use L-glutamate as either a paracrine- or autocrine-like chemical transmitter in a receptor-mediated manner, resulting in inhibition of melatonin synthesis. In this article, we briefly describe the overall features of the microvesicle-mediated signal-transduction mechanism in the pineal gland and discuss the important role of acidic organelles in a novel regulatory mechanism for hormonal synthesis and secretion

ヒト男性生殖器官ABH関連抗原発現メカニズムの組織化学的、分子生物学的解析

科学研究費補助金研究成果報告書研究種目: 一般研究(C)研究期間: 1992～1994課題番号: 04670353研究代表者: 西 克治（滋賀医科大学・医学部・教授）研究分担者: 山田 光子（滋賀医科大学・医学部・助手）研究分担者: 山本 好男（滋賀医科大学・医学部・助手

PARP Inhibitor PJ34 Suppresses Osteogenic Differentiation in Mouse Mesenchymal Stem Cells by Modulating BMP-2 Signaling Pathway

Poly(ADP-ribosyl)ation is known to be involved in a variety of cellular processes, such as DNA repair, cell death, telomere regulation, genomic stability and cell differentiation by poly(ADP-ribose) polymerase (PARP). While PARP inhibitors are presently under clinical investigation for cancer therapy, little is known about their side effects. However, PARP involvement in mesenchymal stem cell (MSC) differentiation potentiates MSC-related side effects arising from PARP inhibition. In this study, effects of PARP inhibitors on MSCs were examined. MSCs demonstrated suppressed osteogenic differentiation after 1 μM PJ34 treatment without cytotoxicity, while differentiation of MSCs into chondrocytes or adipocytes was unaffected. PJ34 suppressed mRNA induction of osteogenic markers, such as Runx2, Osterix, Bone Morphogenetic Protein-2, Osteocalcin, bone sialoprotein, and Osteopontin, and protein levels of Bone Morphogenetic Protein-2, Osterix and Osteocalcin. PJ34 treatment also inhibited transcription factor regulators such as Smad1, Smad4, Smad5 and Smad8. Extracellular mineralized matrix formation was also diminished. These results strongly suggest that PARP inhibitors are capable of suppressing osteogenic differentiation and poly(ADP-ribosyl)ation may play a physiological role in this process through regulation of BMP-2 signaling. Therefore, PARP inhibition may potentially attenuate osteogenic metabolism, implicating cautious use of PARP inhibitors for cancer treatments and monitoring of patient bone metabolism levels

A type of familial cleft of the soft palate maps to 2p24.2–p24.1 or 2p21–p12

Cleft of the soft palate (CSP) and the hard palate are subtypes of cleft palate. Patients with either condition often have difficulty with speech and swallowing. Nonsyndromic, cleft palate isolated has been reported to be associated with several genes, but to our knowledge, there have been no detailed genetic investigations of CSP. We performed a genome-wide linkage analysis using a single-nucleotide polymorphism-based microarray platform and successively using microsatellite markers in a family in which six members, across three successive generations, had CSP. A maximum LOD score of 2.408 was obtained at 2p24.2-24.1 and 2p21-p12, assuming autosomal dominant inheritance. Our results suggest that either of these regions is responsible for this type of CSP

Octaarginine-modified liposomes enhance the anti-oxidant effect of Lecithinized superoxide dismutase by increasing its cellular uptake

The anti-oxidant enzyme superoxide dismutase (SOD) has the potential for use as a therapeutic agent in the treatment of various diseases caused by reactive oxygen species. However, achieving this would be difficult without a suitable delivery system for SOD. We previously reported that PC-SOD, in which four molecules of a phosphatidylcholine (PC) derivative were covalently bound to each dimer of recombinant human CuZnSOD, was a high affinity for the cell membrane (R. Igarashi et al, J. Pharmacol. Exp. Ther. 271 (1994) 1672-7). Here, we show that an octaarginine (R8) modified liposome equipped with PC-SOD (R8-LP (PC-SOD)) enhances its anti-oxidant effect. High-density R8-modified liposomes can stimulate macropinocytosis and are taken up efficiently by cells as demonstrated in a previous study (I.A. Khalil et al. J. Biol. Chem. 281 (2006) 3544-51). Flow cytometry analyses showed that R8-LP (PC-SOD) was taken up by cells more efficiently than PC-SOD. Moreover, R8-LP (PC-SOD) liposomes were found to scavenge superoxide anions (O-2^[-]) very efficiently. These results suggest that the efficient cytosolic delivery of PC-SOD by R8-modified liposomes would enhance the anti-oxidant effects of PC-SOD