Therapy for pneumonitis and sialadenitis by accumulation of CCR2-expressing CD4<Superscript>+</Superscript>CD25<Superscript>+</Superscript>regulatory T cells in MRL/lpr mice

Adoptive transfer of CD4⁺CD25⁺ regulatory T cells has been shown to have therapeutic effects in animal models of autoimmune diseases. Chemokines play an important role in the development of autoimmune diseases in animal models and humans. The present study was performed to investigate whether the progression of organ-specific autoimmune diseases could be reduced more markedly by accumulating chemokine receptor-expressing CD4⁺CD25⁺ regulatory T cells efficiently in target organs in MRL/MpJ-lpr/lpr (MRL/lpr) mice. CD4⁺CD25⁺Foxp3⁺ T cells (Treg cells) and CD4⁺CD25⁺Foxp3⁺ CCR2-transfected T cells (CCR2-Treg cells) were transferred via retro-orbital injection into 12-week-old MRL/lpr mice at the early stage of pneumonitis and sialadenitis, and the pathological changes were evaluated. Expression of monocyte chemoattractant protein-1 (MCP-1)/CCL2 was observed in the lung and submandibular gland of the mice and increased age-dependently. The level of CCR2 expression and MCP-1 chemotactic activity of CCR2-Treg cells were much higher than those of Treg cells. MRL/lpr mice to which CCR2-Treg cells had been transferred showed significantly reduced progression of pneumonitis and sialadenitis in comparison with MRL/lpr mice that had received Treg cells. This was due to more pronounced migration of CCR2-Treg cells and their localization for a longer time in MCP-1-expressing lung and submandibular gland, resulting in stronger suppressive activity. We prepared chemokine receptor-expressing Treg cells and demonstrated their ability to ameliorate disease progression by accumulating in target organs. This method may provide a new therapeutic approach for organ-specific autoimmune diseases in which the target antigens remain undefined.     

Inhibition of ubiquitin ligase F-box and WD repeat domain-containing 7α (Fbw7α) causes hepatosteatosis through Krüppel-like factor 5 (KLF5)/peroxisome proliferator-activated receptor γ2 (PPARγ2) pathway but not SREBP-1c protein in mice

F-box and WD repeat domain-containing 7α (Fbw7α) is the substrate recognition component of a ubiquitin ligase that controls the degradation of factors involved in cellular growth, including c-Myc, cyclin E, and c-Jun. In addition, Fbw7α degrades the nuclear form of sterol regulatory element-binding protein (SREBP)-1a, a global regulator of lipid synthesis, particularly during mitosis in cultured cells. This study investigated the in vivo role of Fbw7α in hepatic lipid metabolism. siRNA knockdown of Fbw7α in mice caused marked hepatosteatosis with the accumulation of triglycerides. However, inhibition of Fbw7α did not change the level of nuclear SREBP-1 protein or the expression of genes involved in fatty acid synthesis and oxidation. In vivo experiments on the gain and loss of Fbw7α function indicated that Fbw7α regulated the expression of peroxisome proliferator-activated receptor (PPAR) γ2 and its target genes involved in fatty acid uptake and triglyceride synthesis. These genes included fatty acid transporter Cd36, diacylglycerol acyltransferase 1 (Dgat1), and fat-specific protein 27 (Cidec). The regulation of PPARγ2 by Fbw7α was mediated, at least in part, by the direct degradation of the Krüppel-like factor 5 (KLF5) protein, upstream of PPARγ2 expression. Hepatic Fbw7α contributes to normal fatty acid and triglyceride metabolism, functions that represent novel aspects of this cell growth regulator.     

In vitro synthesis and characterization of bacteriochlorophyll-<Emphasis Type="Italic">f</Emphasis> and its absence in bacteriochlorophyll-<Emphasis Type="Italic">e</Emphasis> producing organisms

Bacteriochlorophyll(BChl)-f which has not yet been found in natural phototrophs was prepared by chemically modifying chlorophyll-b. The retention time of reverse-phase high-performance liquid chromatography of the synthetic monomeric BChl-f as well as its visible absorption and fluorescence emission spectra in a solution were identified and compared with other naturally occurring chlorophyll pigments obtained from the main light-harvesting antenna systems of green sulfur bacteria, BChls-c/d/e. Based on the above data, BChl-f was below the level of detection in three strains of green photosynthetic bacteria producing BChl-e.     

Dickkopf (Dkk)-3 and β-catenin expressions increased in the transition from normal oral mucosal to oral squamous cell carcinoma

Dickkopf (Dkk)-3, an inhibitor of the Wnt/β-catenin pathway, is reported as a potential tumor suppressor gene in many cancers. To gain a better comprehension of the mechanisms involved in the carcinogenesis of oral squamous epithelium, protein expression and localization of Dkk-3 and β-catenin was investigated in normal epithelium, dysplasias and squamous cell carcinoma (SCC). An increase in β-catenin and Ki-67 expressions was observed from dysplasias to poorly differentiated SCC. Interestingly, an increase in Dkk-3 positive cells was also noted, which was correlated to the cancer progression step. A change in Dkk-3 localization during the transformation of normal oral epithelium to SCC was clearly observed. Dkk-3 was localized in the cell membrane in normal oral epithelium and in dysplasias, whereas that was localized in both cell membrane and cytoplasm in SCC. These results suggest that Dkk-3 is involved in the carcinogenesis of SCC with a distinct function from those in other cancers.     

Antibiotics-free stable polyhydroxyalkanoate (PHA) production from carbon dioxide by recombinant cyanobacteria

A practical antibiotics-free plasmid expression system in cyanobacteria was developed by using the complementation of cyanobacterial recA null mutation with the EscherichiacolirecA gene on the plasmid. This system was applied to the production of polyhydroxyalkanoate (PHA), a biodegradable plastic, and the transgenic cyanobacteria stably maintained the pha genes for PHA production in the antibiotics-free medium, and accumulated up to 52% cell dry weight of PHA.     

Genetically determined nonsusceptibility of the silkworm,Bombyx mori,to infection with a densonucleosis virus (Densovirus)

A nonsusceptible and a highly susceptible strain of the silkworm, Bombyx mori, to peroral infection with a densonucleosis virus (DNV) were studied by probit analysis. Tests with the susceptible and nonsusceptible parent strains, their reciprocal F₁ hybrids, the F₂ hybrid, and the backcrossed hybrids to either of the parents demonstrated that the nonsusceptibility of the silkworm to DNV was inherited and controlled by a recessive gene which was not sex-linked.     

Light activates the adrenal gland: timing of gene expression and glucocorticoid release

Light is a powerful synchronizer of the circadian rhythms, and bright light therapy is known to improve metabolic and hormonal status of circadian rhythm sleep disorders, although its mechanism is poorly understood. In the present study, we revealed that light induces gene expression in the adrenal gland via the suprachiasmatic nucleus (SCN)-sympathetic nervous system. Moreover, this gene expression accompanies the surge of plasma and brain corticosterone levels without accompanying activation of the hypothalamo-adenohypophysial axis. The abolishment after SCN lesioning, and the day-night difference of light-induced adrenal gene expression and corticosterone release, clearly indicate that this phenomenon is closely linked to the circadian clock. The magnitude of corticostereone response is dose dependently correlated with the light intensity. The light-induced clock-dependent secretion of glucocorticoids adjusts cellular metabolisms to the new light-on environment.