Decreases of calcium and phosphorus in monkey cardiac walls with development and aging

To elucidate compositional changes of the cardiac walls with development and aging, the authors investigated changes of elements in the atrial and ventricular walls of monkeys. The left and right atrial walls, left and right ventricular walls, and interatrial and interventricular septa were resected from the subjects. The subjects consisted of 17 rhesus and 13 Japanese monkeys, ranging in age from 10 d to 33 yr. The element content of the cardiac walls was analyzed by inductively coupled plasma-atomic emission spectrometry. The Ca and P contents decreased in all of the left and right atrial and ventricular walls, interatrial septa, and interventricular septa with development, whereas the S and Mg contents decreased in the left and right ventricular walls with development. Regarding the relationships among elements, significant direct correlations were found among Ca, P, Mg, and Zn in all of the left and right atrial walls, left and right ventricular walls, and interatrial and interventricular septa, with some exceptions. As Ca decresed in the cardic walls, P, Mg, and Zn decreased simultaneously in the cardiac walls. The mass ratio of Ca/P decreased gradually with Ca decrease in both the atrial and ventricular walls, but it was not constant.     

PACAP- and PHI-mediated sustained relaxation in circular muscle of gastric fundus: findings obtained in PACAP knockout mice

Mediators of neurogenic responses of the gastric fundus were studied in wild type and pituitary adenylate cyclase activating peptide (PACAP) knockout mice. Electrical field stimulation (EFS) to the circular muscle strips of the wild type mouse fundus induced a tri-phasic response, rapid transient contraction and relaxation, and sustained relaxation that was prolonged for an extended period after the end of EFS. The transient relaxation and contraction were completely inhibited by N(G)-nitro-L-arginine and atropine, respectively. The sustained relaxation was completely inhibited by a PACAP receptors antagonist, PACAP(6-38). The strips prepared from PACAP knockout mice exhibited a large contraction without rapid relaxation and unexpectedly, a sustained relaxation. However, the sustained relaxation was decreased to about a half of that observed in wild type mice. Anti-peptide histidine isoleucine (PHI) serum abolished the sustained relaxation in the knockout mice. The serum partially inhibited the sustained relaxation in wild type mice and PACAP(6-38) abolished the relaxation that remained after the antiserum-treatment. PHI relaxed the strips prepared from wild type mice. The relaxation was completely inhibited by PACAP(6-38). It was concluded that PACAP and PHI separately mediate the sustained relaxation in the mouse gastric fundus, and that nitric oxide and ACh mediate transient relaxation and contraction, respectively.     

Apoptotic myocytes generate monocyte chemoattractant protein-1 and mediate macrophage recruitment.

The mechanisms by which apoptotic myocytes are removed by macrophages have not been fully elucidated. This study examined whether apoptotic myocytes actively recruit macrophages by generating monocyte chemoattractant protein-1 (MCP-1) in experiments in vitro and in vivo. Neonatal rat cardiac myocytes were incubated for 4 h in the presence or absence of staurosporine (STS, 0.2-1 mumol/l), an apoptosis inducer. Nuclear staining with DAPI showed that STS induced apoptosis in a dose-dependent fashion. STS (1 mumol/l) caused extensive DNA fragmentation and increased caspase-3 activity compared with a serum-deprived control. MCP-1 mRNA and protein levels in myocytes increased twofold and fourfold, respectively, on STS treatment, and immunochemical staining revealed that apoptotic myocytes expressed MCP-1. To elucidate the role of MCP-1 expressed in apoptotic myocytes to recruit macrophages/monocytes, rat monocytes were incubated in the supernatant of STS-treated myocytes using a trans-well system. The culture medium of STS-treated myocytes recruited monocytes in a MCP-1-dependent fashion. In addition, experiments were performed in vivo using ischemia-reperfused rat hearts. Rats were subjected to 30 min of ligation of the left coronary artery followed by 24 h of reperfusion. After the reperfusion, in the ischemic border myocardium, 17.1 +/- 1.1% of myocytes were terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) positive. Moreover, double staining using the TUNEL technique and immunohistochemistry with MCP-1 antibody showed that 69.8 +/- 3.9% of TUNEL-positive myocytes expressed MCP-1 protein. Concomitantly, activated macrophages infiltrated the areas of apoptosis remarkably. These results suggest that apoptotic myocytes produce MCP-1, which have a critical role in the active recruitment of macrophages.     

Ontogeny and multipotency of neural crest-derived stem cells in mouse bone marrow, dorsal root ganglia, and whisker pad

Although recent reports have described multipotent, self-renewing, neural crest-derived stem cells (NCSCs), the NCSCs in various adult rodent tissues have not been well characterized or compared. Here we identified NCSCs in the bone marrow (BM), dorsal root ganglia, and whisker pad and prospectively isolated them from adult transgenic mice encoding neural crest-specific P0-Cre/Floxed-EGFP and Wnt1-Cre/Floxed-EGFP. Cultured EGFP-positive cells formed neurosphere-like structures that expressed NCSC genes and could differentiate into neurons, glial cells, and myofibroblasts, but the frequency of the cell types was tissue source dependent. Interestingly, we observed NCSCs in the aorta-gonad-mesonephros region, circulating blood, and liver at the embryonic stage, suggesting that NCSCs migrate through the bloodstream to the BM and providing an explanation for how neural cells are generated from the BM. The identification of NCSCs in accessible adult tissue provides a new potential source for autologous cell therapy after nerve injury or disease.     

COPI–TRAPPII activates Rab18 and regulates its lipid droplet association

The transport protein particle (TRAPP) was initially identified as a vesicle tethering factor in yeast and as a guanine nucleotide exchange factor (GEF) for Ypt1/Rab1. In mammals, structures and functions of various TRAPP complexes are beginning to be understood. We found that mammalian TRAPPII was a GEF for both Rab18 and Rab1. Inactivation of TRAPPII‐specific subunits by various methods including siRNA depletion and CRISPR–Cas9‐mediated deletion reduced lipolysis and resulted in aberrantly large lipid droplets. Recruitment of Rab18 onto lipid droplet (LD) surface was defective in TRAPPII‐deleted cells, but the localization of Rab1 on Golgi was not affected. COPI regulates LD homeostasis. We found that the previously documented interaction between TRAPPII and COPI was also required for the recruitment of Rab18 to the LD. We hypothesize that the interaction between COPI and TRAPPII helps bring TRAPPII onto LD surface, and TRAPPII, in turn, activates Rab18 and recruits it on the LD surface to facilitate its functions in LD homeostasis.     

A novel member of the leucine-rich repeat superfamily induced in rat astrocytes by beta-amyloid.

beta-Amyloid (Abeta) deposition and senile plaque-associated astrocytes are common neuropathological features of Alzheimer's disease (AD). Although the molecular mechanisms by which Abeta contributes to the progression of neuropathologic changes have not been established entirely, there is little doubt that the association of Abeta with astrocytes, the predominant cell type in brain, has significant influence on exacerbation of the disease. In an effort to identify key molecules involved in AD, we investigated Abeta-responsive genes using rat astrocytes. In this study, we identified a novel Abeta-induced rat gene, designated as Lib, encoding a type I transmembrane protein with an extracellular domain that contains fifteen leucine-rich repeats (LRRs). Human counterpart of rat Lib is located on chromosome 3q29 and human Lib mRNA found in particularly placenta. Lib mRNA levels in rat C6 astrocytoma cells can be increased by pro-inflammatory cytokines and the rat Lib-transfected cells express Lib protein on the cell surfaces. Lib appears to be a member of the LRR superfamily which is involved in cell-cell and/or -extracellular matrix interactions including adhesion or target recognition in neuroinflammatory states.     

AsianPerilla crops and their weedy forms: Their cultivation, utilization and genetic relationships

The cultivation and utilization of two Perilla crops were surveyed in Asia. Perilla frutescens var. frutescens is essentially an oil crop and is now widely cultivated in China and Korea. Its seeds are also used as a flavor for traditional foods in Japan, Korea, China and Nepal. In Korea, leaves of var. frutescens are used as a fresh vegetable and for making pickles. Whereas P. frutescens var. crispa is a Chinese medicine and afresh vegetable in the Far East, it has almost disappeared in many parts of Asia. Cultivation of var. crispa is still continued in Japan and Vietnam. In particular, it is cultivated in a large scale for coloring pickles in the areas where a large amount of plum pickles are produced in Japan. In China and Korea, it remains only as a relict form. Weedy plants ofPerilla are found in Japan, Korea and China. We can classify them into two forms; one, which is closely related to var. frutescens, and the other, which is similar to var. crispa We foundP citriodora andR hirtella in Guandong and Jiangxi provinces of China, respectively. It is clear that they are not endemic to Japan. A phylogenetic tree of samples of two Perilla crops and their weedy forms based on RAPD markers revealed that the weedy forms similar to var. crispa and var. frutescens are genetically closely related to var. crispa and var. frutescens, respectively. Var. crispa and its closely related weedy form seem to be more primitive.