New Dihydropyridine Derivative Attenuates NF-κB Activation via Suppression of Calcium Influx in a Mouse BV-2 Microglial Cell Line.

Activated microglia contribute to many neuroinflammatory diseases in the central nervous system. In this study, we attempted to identify an anti-inflammatory compound that could suppress microglial activation. We performed high-throughput screening with a chemical library developed at our institute. We performed a luciferase assay of nuclear factor-kappa B (NF-κB) reporter stable HT22 cells and identified a compound that was confirmed to inhibit the anti-inflammatory response in BV2 microglial cells. The selected dihydropyridine derivative can suppress the expression response of interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor (TNF), as well as NF-κB phosphorylation and nuclear translocation, and reduce the intracellular calcium level. Thus, our identified compound has a potential role in suppressing microglial activation and may contribute to the development of a new therapeutic molecule against neuroinflammatory diseases.

Reduced glutathione level in the aqueous humor of patients with primary open-angle glaucoma and normal-tension glaucoma.

Glaucoma is a leading cause of blindness worldwide in older people. Profiling the aqueous humor, including the metabolites it contains, is useful to understand physiological and pathological conditions in the eye. In the current study, we used mass spectrometry (MS) to characterize the aqueous humor metabolomic profile and biological features of patients with glaucoma. Aqueous humor samples were collected during trabeculectomy surgery or cataract surgery and analyzed with global metabolomics. We included 40 patients with glaucoma (32 with POAG, 8 with NTG) and 37 control subjects in a discovery study. VIP analysis revealed five metabolites that were elevated and three metabolites that were reduced in the glaucoma patients. The identified metabolomic profile had an area under the receiver operating characteristic curve of 0.953. Among eight selected metabolites, the glutathione level was significantly decreased in association with visual field defects. Moreover, in a validation study to confirm the reproducibility of our findings, the glutathione level was reduced in NTG and POAG patients compared with a cataract control group. Our findings demonstrate that aqueous humor profiling can help to diagnose glaucoma and that various aqueous humor metabolites are correlated with clinical parameters in glaucoma patients. In addition, glutathione is clearly reduced in the aqueous humor of glaucoma patients with both IOP-dependent and IOP-independent disease subtypes. These findings indicate that antioxidant agents in the aqueous humor reflect glaucomatous optic nerve damage and that excessive oxidative stress may be involved in the pathogenesis of glaucoma.

Constitutive CD8 expression drives innate CD8+ T-cell differentiation via induction of iNKT2 cells.

Temporal down-regulation of the CD8 co-receptor after receiving positive-selection signals has been proposed to serve as an important determinant to segregate helper versus cytotoxic lineages by generating differences in the duration of TCR signaling between MHC-I and MHC-II selected thymocytes. By contrast, little is known about whether CD8 also modulates TCR signaling engaged by the non-classical MHC-I-like molecule, CD1d, during development of invariant natural killer T (iNKT) cells. Here, we show that constitutive transgenic CD8 expression resulted in enhanced differentiation of innate memory-like CD8+ thymocytes in both a cell-intrinsic and cell-extrinsic manner, the latter being accomplished by an increase in the IL-4-producing iNKT2 subset. Skewed iNKT2 differentiation requires cysteine residues in the intracellular domain of CD8α that are essential for transmitting cellular signaling. Collectively, these findings shed a new light on the relevance of CD8 down-regulation in shaping the balance of iNKT-cell subsets by modulating TCR signaling.

Essential functions of Runx/Cbfß in gut conventional dendritic cells for priming Rorγt+ T cells.

Acquired immune responses are initiated by activation of CD4+ helper T (Th) cells via recognition of antigens presented by conventional dendritic cells (cDCs). DCs instruct Th-cell polarization program into specific effector Th subset, which will dictate the type of immune responses. Hence, it is important to unravel how differentiation and/or activation of DC are linked with Th-cell-intrinsic mechanism that directs differentiation toward a specific effector Th subset. Here, we show that loss of Runx/Cbfß transcription factors complexes during DC development leads to loss of CD103+CD11b+ cDC2s and alters characteristics of CD103-CD11b+ cDCs in the intestine, which was accompanied with impaired differentiation of Rorγt+ Th17 cells and type 3 Rorγt+ regulatory T cells. We also show that a Runx-binding enhancer in the Rorc gene is essential for T cells to integrate cDC-derived signals to induce Rorγt expression. These findings reveal that Runx/Cbfß complexes play crucial and complementary roles in cDCs and Th cells to shape converging type 3 immune responses.

Growth differentiation factor 6 derived from mesenchymal stem/stromal cells reduces age-related functional deterioration in multiple tissues.

The senescence-associated secretory phenotype (SASP) has attracted attention as a mechanism that connects cellular senescence to tissue dysfunction, and specific SASP factors have been identified as systemic pro-aging factors. However, little is known about the age-dependent changes in the secretory properties of stem cells. Young, but not old, mesenchymal stem/stromal cells (MSCs) are a well-known source of critical regenerative factors, but the identity of these factors remains elusive. In this study, we identified growth differentiation factor 6 (Gdf6; also known as Bmp13 and CDMP-2) as a regenerative factor secreted from young MSCs. The expression of specific secretory factors, including Gdf6, was regulated by the microRNA (miRNA) miR-17, whose expression declined with age. Upregulation of Gdf6 restored the osteogenic capacity of old MSCs in vitro and exerted positive effects in vivo on aging-associated pathologies such as reduced lymphopoiesis, insufficient muscle repair, reduced numbers of neural progenitors in the brain, and chronic inflammation. Our results suggest that manipulation of miRNA could enable control of the SASP, and that regenerative factors derived from certain types of young cells could be used to treat geriatric diseases.