OBJECTIVEThe significant roles of brown adipose tissue (BAT) in the regulation of energy expenditure and adiposity are established in small rodents but have been controversial in humans. The objective is to examine the prevalence of metabolically active BAT in healthy adult humans and to clarify the effects of cold exposure and adiposity.RESEARCH DESIGN AND METHODSIn vivo 2-[18F]fluoro-2-deoxyglucose (FDG) uptake into adipose tissue was measured in 56 healthy volunteers (31 male and 25 female subjects) aged 23–65 years by positron emission tomography (PET) combined with X-ray computed tomography (CT).RESULTSWhen exposed to cold (19°C) for 2 h, 17 of 32 younger subjects (aged 23–35 years) and 2 of 24 elderly subjects (aged 38–65 years) showed a substantial FDG uptake into adipose tissue of the supraclavicular and paraspinal regions, whereas they showed no detectable uptake when kept warm (27°C). Histological examinations confirmed the presence of brown adipocytes in these regions. The cold-activated FDG uptake was increased in winter compared with summer (P < 0.001) and was inversely related to BMI (P < 0.001) and total (P < 0.01) and visceral (P < 0.001) fat areas estimated from CT image at the umbilical level.CONCLUSIONSOur findings, being against the conventional view, indicate the high incidence of metabolically active BAT in adult humans and suggest a role in the control of body temperature and adiposity.

Canonical transient receptor potential (TRPC) channels control influxes of Ca 2؉ and other cations that induce diverse cellular processes upon stimulation of plasma membrane receptors coupled to phospholipase C (PLC). Invention of subtype-specific inhibitors for TRPCs is crucial for distinction of respective TRPC channels that play particular physiological roles in native systems. Here, we identify a pyrazole compound (Pyr3), which selectively inhibits TRPC3 channels. Structure-function relationship studies of pyrazole compounds showed that the trichloroacrylic amide group is important for the TRPC3 selectivity of Pyr3. Electrophysiological and photoaffinity labeling experiments reveal a direct action of Pyr3 on the TRPC3 protein. In DT40 B lymphocytes, Pyr3 potently eliminated the Ca 2؉ influx-dependent PLC translocation to the plasma membrane and late oscillatory phase of B cell receptorinduced Ca 2؉ response. Moreover, Pyr3 attenuated activation of nuclear factor of activated T cells, a Ca 2؉ -dependent transcription factor, and hypertrophic growth in rat neonatal cardiomyocytes, and in vivo pressure overload-induced cardiac hypertrophy in mice. These findings on important roles of native TRPC3 channels are strikingly consistent with previous genetic studies. Thus, the TRPC3-selective inhibitor Pyr3 is a powerful tool to study in vivo function of TRPC3, suggesting a pharmaceutical potential of Pyr3 in treatments of TRPC3-related diseases such as cardiac hypertrophy.Ca 2ϩ signaling ͉ pyrazole compounds ͉ TRPC channels ͉ TRPC3

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Natural plant viruses are rodlike or spherical nanoassemblies with discrete size and morphology, in which genome nucleic acids are encapsulated by self-assembled coat proteins (capsids). Most capsids in spherical viruses have an icosahedral symmetry and the number and arrangement of subunits are related to the triangulation number (T number), which is derived from quasi-equivalence theory.[1] For example, tomato bushy stunt virus (TBSV, T = 3) consists of 180 quasi-equivalent protein subunits that comprise 388 amino acids each (diameter of capsid ca. 33 nm). [2] Recently, the application of bacteriophages such as M13 phage [3] and plant viruses [4] such as tobacco mosaic virus (TMV), [5] cowpea mosaic virus (CPMV), [6] and cowpea chlorotic mottle virus (CCMV) [7] in nanotechnology have attracted much attention because of their fascinating nanostructures with a discrete nanospace. Virus nanotechnologies depend on the structure of "ready-made" capsids, however, the chemical strategy of de novo designed "tailor-made" viruslike nanocapsules is still in its infancy. The development of designed capsid molecules for the reconstruction of viral architectures would enhance the potential of viruslike nanocapsules and notably contribute to advance nanobioscience. To date, virus-inspired nanocapsules with a size of about 1-5 nm have been self-assembled by hydrogen bonds [8] and coordination bonds. [9] However, the size of these supramolecular nanocapsules is evidently smaller than that of natural viruses, and consequently their applications have been limited to the inclusion of small guest molecules. Yeates and coworkers have developed a general strategy for the construction of protein architectures, such as cages and filaments, by the use of fusion proteins.[10] We have demonstrated that virus-inspired C 3 -symmetric b-sheet-forming peptide conjugates self-assemble into nanocapsules [11a,c] and nanofibers. [11b,c] Recently, we have also reported that C 3 -symmetric glutathione conjugates self-assemble into nanospheres.[11d, e]Herein we show a first example of a synthetic viral capsid self-assembled from a 24-mer b-annulus peptide (1: INHVGGTGGAIMAPVAVTRQLVGS) in water ( Figure 1). The b-annulus peptide motif (Ile69-Ser92) in the TBSV capsid participates in the formation of a dodecahedral internal skeleton, [2b] thus we expected that the peptide 1 Figure 1. Illustration of the hypothesized formation of viruslike nanocapsules by self-assembly of 24-mer b-annulus peptide 1.

Activation of Ca2؉ signaling induced by receptor stimulation and mechanical stress plays a critical role in the development of cardiac hypertrophy. A canonical transient receptor potential protein subfamily member, TRPC6, which is activated by diacylglycerol and mechanical stretch, works as an upstream regulator of the Ca 2؉ signaling pathway. Although activation of protein kinase G (PKG) inhibits TRPC6 channel activity and cardiac hypertrophy, respectively, it is unclear whether PKG suppresses cardiac hypertrophy through inhibition of TRPC6. Here, we show that inhibition of cGMP-selective PDE5 (phosphodiesterase 5) suppresses endothelin-1-, diacylglycerol analog-, and mechanical stretch-induced hypertrophy through inhibition of Ca 2؉ influx in rat neonatal cardiomyocytes. influx. Substitution of Ala for Thr 69 in TRPC6 abolished the anti-hypertrophic effects of PDE5 inhibition. In addition, chronic PDE5 inhibition by oral sildenafil treatment actually induced TRPC6 phosphorylation in mouse hearts. Knockdown of RGS2 (regulator of G protein signaling 2) and RGS4, both of which are activated by PKG to reduce G␣ q -mediated signaling, did not affect the suppression of receptor-activated Ca 2؉ influx by PDE5 inhibition. These results suggest that phosphorylation and functional suppression of TRPC6 underlie prevention of pathological hypertrophy by PDE5 inhibition.Pathological hypertrophy of the heart, induced by pressure overload, such as chronic hypertension and aortic stenosis, is a major risk factor for heart failure and cardiovascular mortality (1). Neurohumoral factors, such as norepinephrine, angiotensin II (Ang II), 2 and endothelin-1 (ET-1), and mechanical stress are believed to be prominent contributors for pressure overloadinduced cardiac hypertrophy (2, (9). A partial depolarization of plasma membrane by receptor stimulation is reported to increase the frequency of Ca 2ϩ oscillations, leading to activation of nuclear factor of activated T cells (NFAT), a transcription factor that is predominantly regulated by calcineurin (10). Recent reports have indicated that transient receptor potential canonical (TRPC) subfamily proteins play an essential role in agonistinduced membrane depolarization (11, 12). The relevance of TRPC channels to pathological hypertrophy is underscored by the observations that heart-targeted transgenic mice expressing TRPC channels caused hypertrophy (13,14) and that TRPC proteins were up-regulated in hypertrophied and failing hearts (14 -17). Among seven TRPC subfamilies, increased channel activities of TRPC1, TRPC3, and TRPC6 have been implicated in cardiac hypertrophy in vivo. TRPC1 is known to function not * This study was supported by grants from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (to M. Nishida, M. Nakaya, and H. Kurose), a grant-in-aid for scientific research on Innovative Areas (to M. Nishida), a grant-in-aid for scientific research on Priority Areas (H. Kurose), and grants from the Naito Foundation, the Nakatomi Foundation, the Sapporo ...