Heat Stress Modulates Both Anabolic and Catabolic Signaling Pathways Preventing Dexamethasone‐Induced Muscle Atrophy In Vitro

It is generally recognized that synthetic glucocorticoids induce skeletal muscle weakness, and endogenous glucocorticoid levels increase in patients with muscle atrophy. It is reported that heat stress attenuates glucocorticoid‐induced muscle atrophy; however, the mechanisms involved are unknown. Therefore, we examined the mechanisms underlying the effects of heat stress against glucocorticoid‐induced muscle atrophy using C2C12 myotubes in vitro, focusing on expression of key molecules and signaling pathways involved in regulating protein synthesis and degradation. The synthetic glucocorticoid dexamethasone decreased myotube diameter and protein content, and heat stress prevented the morphological and biochemical glucocorticoid effects. Heat stress also attenuated increases in mRNAs of regulated in development and DNA damage responses 1 (REDD1) and Kruppel‐like factor 15 (KLF15). Heat stress recovered the dexamethasone‐induced inhibition of PI3K/Akt signaling. These data suggest that changes in anabolic and catabolic signals are involved in heat stress‐induced protection against glucocorticoid‐induced muscle atrophy. These results have a potentially broad clinical impact because elevated glucocorticoid levels are implicated in a wide range of diseases associated with muscle wasting. J. Cell. Physiol. 232: 650–664, 2017. © 2016 The Authors. Journal of Cellular Physiology published by Wiley Periodicals, Inc.     

Essential role of the PSI–LHCII supercomplex in photosystem acclimation to light and/or heat conditions by state transitions

Light and temperature affect state transitions through changes in the plastoquinone (PQ) redox state in photosynthetic organisms. We demonstrated that light and/or heat treatment induced preferential photosystem (PS) I excitation by binding light-harvesting complex II (LHCII) proteins. The photosystem of wheat was in state 1 after dark overnight treatment, wherein PQ was oxidized and most of LHCII was not bound to PSI. At the onset of the light treatment [25 °C in the light (100 µmol photons m^?2 s^?1)], two major LHCIIs, Lhcb1 and Lhcb2 were phosphorylated, and the PSI–LHCII supercomplex formed within 5 min, which coincided with an increase in the PQ oxidation rate. Heat treatment at 40 °C of light-adapted wheat led to further LHCII protein phosphorylation of, resultant cyclic electron flow promotion, which was accompanied by ultrafast excitation of PSI and structural changes of thylakoid membranes, thereby protecting PSII from heat damage. These results suggest that LHCIIs are required for the functionality of wheat plant PSI, as it keeps PQ oxidized by regulating photochemical electron flow, thereby helping acclimation to environmental changes.     

Risk factors for bone loss in patients with rheumatoid arthritis treated with biologic disease-modifying anti-rheumatic drugs

Objective

Osteoporosis is a complication of rheumatoid arthritis. We examined the risk factors for bone loss in rheumatoid arthritis patients receiving biological disease-modifying anti-rheumatic drugs. Lumbar spine and femoral neck bone mineral density was measured at two time points in 153 patients with rheumatoid arthritis managed with biological disease-modifying anti-rheumatic drugs. We examined patients’ variables to identify risk factors for least significant reduction of bone mineral density.

Results

Least significant reduction of lumbar spine bone mineral density (≤ ? 2.4%) was seen in 13.1% of patients. Least significant reduction of femoral neck bone mineral density (≤ ? 1.9%) was seen in 34.0% of patients. Multiple logistic regression analysis showed that a risk factor for least significant reduction of the lumbar spine was high-dose methylprednisolone use. Multiple regression analysis showed that a risk factor for least significant reduction of the femoral neck was short disease duration. Our findings showed that a risk factor for femoral neck bone mineral density reduction was a short disease duration. These findings suggest that rheumatoid arthritis patients receiving treatment with biological disease-modifying anti-rheumatic drugs may benefit from earlier osteoporosis treatments to prevent femoral neck bone loss.

     

Complete Genome Sequence of Finegoldia magna, an Anaerobic Opportunistic Pathogen

Finegoldia magna (formerly Peptostreptococcus magnus), a memberof the Gram-positive anaerobic cocci (GPAC), is a commensalbacterium colonizing human skin and mucous membranes. Moreover,it is also recognized as an opportunistic pathogen responsiblefor various infectious diseases. Here, we report the completegenome sequence of F. magna ATCC 29328. The genome consistsof a 1 797 577 bp circular chromosome and an 189 163bp plasmid (pPEP1). The metabolic maps constructed based onthe genome information confirmed that most F. magna strainscannot ferment most sugars, except fructose, and have variousaminopeptidase activities. Three homologs of albumin-bindingprotein, a known virulence factor useful for antiphagocytosis,are encoded on the chromosome, and one albumin-binding proteinhomolog is encoded on the plasmid. A unique feature of the genomeis that F. magna encodes many sortase genes, of which substratesmay be involved in bacterial pathogenesis, such as antiphagocytosisand adherence to the host cell. The plasmid pPEP1 encodes sevensortase and seven substrate genes, whereas the chromosome encodesfour sortase and 19 substrate genes. These plasmid-encoded sortasesmay play important roles in the pathogenesis of F. magna byenriching the variety of cell wall anchored surface proteins.     

Solvent effects on excitation relaxation dynamics of a keto-carotenoid, siphonaxanthin

Solvent effects on relaxation dynamics of a keto-carotenoid, siphonaxanthin, were investigated by means of the femtosecond time-resolved fluorescence spectroscopy. After excitation to the S2 state of siphonaxanthin, the S2-->1(n, pi*) internal conversion occurred with a time constant of 30-35 fs, followed by the 1(n, pi*)-->S1 internal conversion in 180-200 fs. Solvent dependence of the internal conversions was small, however intensities of the S1 fluorescence with its lifetime of longer than 10 ps were enhanced in methanol. These were explained by displacement of the potential surfaces and interaction through the hydrogen-bond between the C=O group of siphonaxanthin and solvents.     

A cell polarity protein aPKCλ is required for eye lens formation and growth

The organisation of individual cells into a functional three-dimensional tissue is still a major question in developmental biology. Modulation of epithelial cell shape is a critical driving force in forming tissues. This is well illustrated in the eye lens where epithelial cells elongate extensively during their differentiation into fibre cells. It is at the lens equator that epithelial cells elongate along their apical-basal axis. During this process the elongating epithelial cells and their earliest fibre cell derivatives remain anchored at their apical tips, forming a discrete region or modiolus, which we term the lens fulcrum. How this is achieved has received scant attention and is little understood. Here, we show that conditional depletion of aPKCλ, a central effector of the PAR polarity complex, disrupts the apical junctions in elongating epithelial cells so that the lens fulcrum fails to form. This results in disorganised fibre cell alignment that then causes cataract. Interestingly, aPKCλ depletion also promotes epithelial-mesenchymal transition of the lens epithelial cells, reducing their proliferation, leading ultimately to a small lens and microphthalmia. These observations indicate that aPKCλ, a regulator of polarity and apical junctions, is required for development of a lens that is the correct size and shape.     

Do aphid galls provide good nutrients for the aphids?: Comparisons of amino acid concentrations in galls among Tetraneura species (Aphididae: Eriosomatinae)

Some aphid species induce leaf galls, in which the fundatrix parthenogenetically produces many nymphs. In order to ensure high performance, galls have to provide the aphids with sufficient nutrients, in particular, amino acids as a nitrogen source. We tested this hypothesis using six Tetraneura aphid species that induce closed galls. We extracted free amino acids from the whole gall tissues of unit weight and quantified the concentration of each amino acid. There were large differences in the total amino acid concentrations among galls of the Tetraneura species. Tetraneura species in which higher concentrations of total amino acids were found in the gall tended to produce larger numbers of offspring. Of the amino acids found, asparagine was predominant in the gall. The asparagine concentration in T. yezoensis galls was several hundred times as high as in control leaves. We discussed why such a high level of asparagine accumulates in aphid galls.     

Establishment of Hertwig's epithelial root sheath cell line from cells involved in epithelial-mesenchymal transition

The epithelial–mesenchymal transition (EMT) is an important event in the developmental process of various organs. In periodontal development during root formation of a tooth, this EMT has been a subject of controversy. Hertwig’s epithelial root sheath (HERS), consisting of two epithelial layers, plays a role of inducing odontogenesis during root development and thereafter becomes fragmented. Some researchers have maintained that in the process of this fragmentation, some HERS cells change from epithelial to mesenchymal cells. Here, we established a HERS cell line (HERS01a) and examined its gene and protein expression. Immunohistochemical staining and real-time PCR analysis showed that HERS01a cells expressed vimentin and N-cadherin as mesenchymal markers as well as cytokeratin14, E-cadherin, and p63 as epithelial stem cell markers. In the presence of TGF-β, HERS01a cells also expressed many more mesenchymal markers, as well as snail1 and 2 as EMT markers. Taken together, our data show that HERS01a displayed unique features associated with EMT in the root formation process, and will thus be useful for analyzing the biological characteristics of HERS and the molecular mechanism underlying the EMT.     

Modulation of viability of live cells by focused ion‐beam exposure

Introduction of membrane‐impermeant substances into living cells is the key method to understand contemporary cellular processes by investigating cellular responses and phenotypes. Here, we performed gold ion beam exposure into live cells by using the focused ion beam implantation method, which was originally developed to precisely control semiconductor device performances. We evaluated the viability of the gold‐irradiated cells by measuring the concentration of adenosine triphosphate (ATP), which is an intracellular energy source produced in the mitochondrial membrane. The viability of the irradiated cells was found to be 20% higher than that of the unirradiated control cells. The atoms might promote the energy generating processes within the mitochondrion. Our results suggest that the viability of living cells can be modulated by accurately controlling the dopant atom numbers. Our technique may be considered as a potential tool in life and medical sciences to quantitatively elucidate the dose‐dependent effects of dopants. Biotechnol. Bioeng. 2011; 108:222–225. © 2010 Wiley Periodicals, Inc.     

Depressive symptoms of female nursing staff working in stressful environments and their association with serum creatine kinase and lactate dehydrogenase – a preliminary study

Background

The activity of creatine kinase (CK) in serum has recently been reported to be potentially associated with several types of depression. The aim of this study is to evaluate whether serum enzymes, including CK, vary even in a healthy population with depressive symptoms caused by work-related stress. We gave questionnaires and blood examinations to 93 healthy female nursing home workers and did an enzyme-linked immunosorbent assay for the quantitative detection of CK isozyme muscle-type M chain (CK-MM) in serum.

Findings

Depressive symptoms were determined using the Center for Epidemiologic Studies Depression (CES-D) scale and compared with the results of the blood examination and serum CK-MM levels. The CES-D results showed significant negative correlations with total CK and lactate dehydrogenase (LDH) activities and CK-MM level (r?=?-0.29, p?=?0.0062; r?=?-0.29, p?=?0.0065; r?=?-0.33, p?=?0.0016, respectively).

Conclusions

Total CK and LDH activities and serum CK-MM level appear to be associated with the depressive symptoms of healthy nurses working in stressful environments, although the significance level was relatively low. The simultaneous detection of serum CK and LDH activities or serum CK-MM level and LDH activity may be useful as an indicator of depressive symptoms, at least for female nursing staff with work-related stress.