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Cancer cachexia causes anorexia and metabolic disorders, eventually leading to sarcopenia, which in turn contributes to the development of functional disabilities. Although anamorelin hydrochloride tablets are marketed to treat cancer cachexia, their efficacy varies significantly among patients. Here, we investigated the efficacy of anamorelin and the factors associated with weight gain. The factors that contributed to weight gain in patients before starting anamorelin were as follows: the patients' disease stage had not progressed to refractory cachexia based on the cancer cachexia classification of the European Palliative Care Research Collaborative; the patients had received fewer lines of anticancer treatment at the start of oral administration of anamorelin; and the patients had not met all the criteria for starting treatment with anamorelin, namely, C-reactive protein level >0.5 mg/dL, hemoglobin level <12 g/dL, and albumin level <3.2 g/dL. These results suggest that early administration of anamorelin hydrochloride tablets may increase the response rate when cancer cachexia is diagnosed.

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Astrocyte-microglia communication influences the onset and progression of central nervous system (CNS) disorders. In this study, we determined how chronic inflammation by activated astrocytes affected and regulated CNS functions in Sandhoff disease (SD), a CNS lysosomal storage disorder. SD triggers intense CNS inflammation such as microglial activation and astrogliosis. It is caused by mutation of the HEXB gene, which reduces ß-hexosaminidase (Hex) enzymatic activity in lysosomes, leading to accumulation of the substrate GM2 ganglioside in neuronal cells. Hexb-/- mice display a phenotype similar to human patients that suffer from chronic inflammation characterized by activation of astrocytes and microglia. In Hexb-/- mice, tremors and loss of muscle coordination begins at ~12 weeks. Interestingly, we found that reactive astrocytes expressed adenosine A2A receptor in the cerebral cortices of Hexb-/- mice at the later inflammatory phase. In cultured astrocytes, expression of A2A receptor could be induced by astrocyte defined medium, and then the activation of the A2A receptor induced ccl2 expression. In Hexb-/- mice, inhibition of the A2A receptor antagonized by istradefylline decreased the number of activated microglial cells and inflammatory cytokines/chemokines at 13 weeks. Thus, the astrocytic A2A receptor is an important sensor that regulates microglial activation in the late phase of inflammation.

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Retinoic acid-inducible gene-I (RIG-I)-like receptors [RLRs; RIG-I and melanoma differentiation-associated gene 5 (MDA5)] sense virus-derived RNA or a synthetic analog of double-stranded RNA polyinosinic-polycytidylic acid [poly(I:C)] and are responsible for host defense against viruses. However, it remains unclear whether radiation affects RLRs. Therefore, the present study investigated the effects of ionizing radiation on RIG-I and MDA5 expression and the response to poly(I:C) using THP1 (human monocytic cell line)-derived macrophages. Non- and X-irradiated (1-10 Gy) macrophages expressed RIG-I and MDA5 at mRNA and protein levels and there was no significant difference in the expression levels. Non- and X-irradiated macrophages expressed antiviral cytokine interferon (IFN)-ß mRNA following poly(I:C)-low molecular weight/LyoVec™ and poly(I:C)-high molecular weight/LyoVec™ stimulation, the agonist of RIG-I and MDA5, respectively. In line with the results of the expression of RIG-I and MDA5, no significant difference in the expression of IFN-ß mRNA was observed between non- and X-irradiation. These results indicate that ionizing radiation hardly affects RLR expression and the response to their agonist poly(I:C) in THP1-derived macrophages.

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Pattern recognition receptors recognize pathogen-associated molecular patterns. Among these, Toll-like receptors (TLRs) have well-characterized roles in antibacterial and antiviral immunity. In the present study, the effects of ionizing radiation on the expression of TLRs and cellular responses to ligands were investigated in THP1 monocytes (human monocytic leukemia cells) and THP1-derived macrophage cells (macrophage-like cells), which are induced by culturing in the presence of phorbol 12-myristate 13-acetate. TLR2 and TLR4 expression was detected in THP1 and macrophage-like cells. X-irradiation caused increased expression of these TLRs in THP1 and decreased expression in macrophage-like cells. Responses to FSL-1 (TLR2 ligand) and lipopolysaccharide (LPS, TLR4 ligand) were estimated by determining the induction of tumor necrosis factor-α (TNF-α). After FSL-1 or LPS stimulation, TNF-α induction was greater in X-irradiated THP1 monocytes than in non-irradiated cells. However, although TNF-α expression was not affected by X-irradiation in macrophage-like cells, the expression of LPS-inducible interferon-ß was lower following X-irradiation of macrophage-like cells. To clarify the mechanisms of TLR2 and TLR4 regulation by X-irradiation, expression of mitogen-activated protein kinase was investigated. These experiments showed that c-Jun N-terminal kinase (JNK) mediated increases in TLR expression in X-irradiated THP1 monocytes and decreases in TLR expression in X-irradiated macrophage-like cells. This study demonstrates that ionizing radiation modulates ligand-responsive TLR expression through the JNK pathway, depending on differentiation state.

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It is essential to know the detailed structure of the thin filament to understand the regulation mechanism of striated muscle contraction. Fluorescence resonance energy transfer (FRET) was used to construct an atomic model of the actin-tropomyosin (Tm)-troponin (Tn) core domain complex. We generated single-cysteine mutants in the 167-195 region of Tm and in TnC, TnI, and the ß-TnT 25-kDa fragment, and each was attached with an energy donor probe. An energy acceptor probe was located at actin Gln41, actin Cys374, or the actin nucleotide-binding site. From these donor-acceptor pairs, FRET efficiencies were determined with and without Ca(2+). Using the atomic coordinates for F-actin, Tm, and the Tn core domain, we searched all possible arrangements for Tm or the Tn core domain on F-actin to calculate the FRET efficiency for each donor-acceptor pair in each arrangement. By minimizing the squared sum of deviations for the calculated FRET efficiencies from the observed FRET efficiencies, we determined the location of Tm segment 167-195 and the Tn core domain on F-actin with and without Ca(2+). The bulk of the Tn core domain is located near actin subdomains 3 and 4. The central helix of TnC is nearly perpendicular to the F-actin axis, directing the N-terminal domain of TnC toward the actin outer domain. The C-terminal region in the I-T arm forms a four-helix-bundle structure with the Tm 175-185 region. After Ca(2+) release, the Tn core domain moves toward the actin outer domain and closer to the center of the F-actin axis.

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Fluorescence resonance energy transfer (FRET) was used to construct an atomic model of the actin-tropomyosin (Tm) complex on a reconstituted thin filament. We generated five single-cysteine mutants in the 146-174 region of rabbit skeletal muscle α-Tm. An energy donor probe was attached to a single-cysteine Tm residue, while an energy acceptor probe was located in actin Gln41, actin Cys374, or the actin nucleotide binding site. From these donor-acceptor pairs, FRET efficiencies were determined with and without Ca(2+). Using the atomic coordinates for F-actin and Tm, we searched all possible arrangements for Tm segment 146-174 on F-actin to calculate the FRET efficiency for each donor-acceptor pair in each arrangement. By minimizing the squared sum of deviations for the calculated FRET efficiencies from the observed FRET efficiencies, we determined the location of the Tm segment on the F-actin filament. Furthermore, we generated a set of five single-cysteine mutants in each of the four Tm regions 41-69, 83-111, 216-244, and 252-279. Using the same procedures, we determined each segment's location on the F-actin filament. In the best-fit model, Tm runs along actin residues 217-236, which were reported to compose the Tm binding site. Electrostatic, hydrogen-bonding, and hydrophobic interactions are involved in actin and Tm binding. The C-terminal region of Tm was observed to contact actin more closely than did the N-terminal region. Tm contacts more residues on actin without Ca(2+) than with it. Ca(2+)-induced changes on the actin-Tm contact surface strongly affect the F-actin structure, which is important for muscle regulation.

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