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Introduction Diagnosing vasculitis is frequently difficult because its clinical symptoms are similar to those of common infectious diseases and other inflammatory disorders. This study focused on chemokine receptor 8 (CCR8) in peripheral blood mononuclear cells to find a new biomarker that distinguishes vasculitis from infectious complications. Methods A cross-sectional study was conducted among 113 patients with systemic vasculitis who were referred to Japan Health Care Organization Sendai Hospital from 2014 to 2016, including those with antineutrophil cytoplasmic antibody (ANCA)−associated vasculitis, anti−glomerular basement membrane disease, lupus nephritis, and Henoch-Schonlein purpura. Peripheral blood mononuclear cells were extracted from blood, and CCR8 expression was examined by real time polymerase chain reaction and flow cytometry. Results CCR8 gene expression was significantly higher in patients with ANCA-associated vasculitis, which was confirmed by upregulated CCR8 protein expression in flow cytometry (P < 0.001 and P = 0.01, respectively). Neither lupus nephritis nor Henoch-Schonlein purpura showed upregulated CCR8. Elevated CCR8 in the active phase decreased significantly in remission (P = 0.002), which was correlated with decreased serum inflammatory markers. Despite elevated serological inflammatory markers, the CCR8 levels at the time of infection, including bacterial, viral, and fungal, did not increase, indicating that infectious complications did not affect CCR8 expression (P = 0.02). Conclusion CCR8 in peripheral blood mononuclear cells may be a useful diagnostic marker for ANCA-associated vasculitis to differentiate between active vasculitis and infectious inflammation.

Sporadic inclusion body myositis (sIBM) is the most common idiopathic inflammatory myopathy, and several reports have suggested that mitochondrial abnormalities are involved in its etiology.We recruited 9 sIBM patients and found significant histological changes and an elevation of growth differential factor 15 (GDF15), a marker of mitochondrial disease, strongly suggesting the involvement of mitochondrial dysfunction. Bioenergetic analysis of sIBM patient myoblasts revealed impaired mitochondrial function.Decreased ATP production, reduced mitochondrial size and reduced mitochondrial dynamics were also observed in sIBM myoblasts. Cell vulnerability to oxidative stress also suggested the existence of mitochondrial dysfunction.Mitochonic acid-5 (MA-5) increased the cellular ATP level, reduced mitochondrial ROS, and provided protection against sIBM myoblast death.MA-5 also improved the survival of sIBM skin fibroblasts as well as mitochondrial morphology and dynamics in these cells. The reduction in the gene expression levels of Opa1 and Drp1 was also reversed by MA-5, suggesting the modification of the fusion/fission process. These data suggest that MA-5 may provide an alternative therapeutic strategy for treating not only mitochondrial diseases but also sIBM.

Mitochondrial dysfunction increases oxidative stress and depletes ATP in a variety of disorders. Several antioxidant therapies and drugs affecting mitochondrial biogenesis are undergoing investigation, although not all of them have demonstrated favorable effects in the clinic. We recently reported a therapeutic mitochondrial drug mitochonic acid MA-5 (Tohoku J. Exp. Med., 2015). MA-5 increased ATP, rescued mitochondrial disease fibroblasts and prolonged the life span of the disease model “Mitomouse” (JASN, 2016). To investigate the potential of MA-5 on various mitochondrial diseases, we collected 25 cases of fibroblasts from various genetic mutations and cell protective effect of MA-5 and the ATP producing mechanism was examined. 24 out of the 25 patient fibroblasts (96%) were responded to MA-5. Under oxidative stress condition, the GDF-15 was increased and this increase was significantly abrogated by MA-5. The serum GDF-15 elevated in Mitomouse was likewise reduced by MA-5. MA-5 facilitates mitochondrial ATP production and reduces ROS independent of ETC by facilitating ATP synthase oligomerization and supercomplex formation with mitofilin/Mic60. MA-5 reduced mitochondria fragmentation, restores crista shape and dynamics. MA-5 has potential as a drug for the treatment of various mitochondrial diseases. The diagnostic use of GDF-15 will be also useful in a forthcoming MA-5 clinical trial., Graphical Abstract Image 1, Highlights • MA-5 rescues patient's cell survival independent of genetic mutation backgrounds. • MA-5 promotes ATP synthase dimer formation followed by the precipitation of supercomplex. • The cell protective effect of MA-5 will be predicted by GDF-15 in vitro and in vivo. Mitochondrial diseases are life-threatening and progressive, yet largely untreatable because of the lack of adequate drug. We found a mitochondria-homing drug Mitochonic acid-5 (MA-5) that facilitates ATP production and restoring mitochondrial dynamics, rescuing a wide variety of human mitochondrial diseases cell survival. MA-5 binds to mitochondrial protein mitofilin/Mic60 and facilitating ATP synthase oligomerization and supercomplex formation that increase local ATP production, even under the genetically proton-limited condition in mitochondrial diseases. Therefore, MA-5 will be a candidate chemical for modulating mitochondrial function and remedy for not only mitochondrial diseases but also mitochondrial-related diseases (diabetes, diabetic nephropathy, cardiomyopathy, longevity etc.).

Diabetic kidney disease is a major cause of renal failure that urgently necessitates a breakthrough in disease management. Here we show using untargeted metabolomics that levels of phenyl sulfate, a gut microbiota-derived metabolite, increase with the progression of diabetes in rats overexpressing human uremic toxin transporter SLCO4C1 in the kidney, and are decreased in rats with limited proteinuria. In experimental models of diabetes, phenyl sulfate administration induces albuminuria and podocyte damage. In a diabetic patient cohort, phenyl sulfate levels significantly correlate with basal and predicted 2-year progression of albuminuria in patients with microalbuminuria. Inhibition of tyrosine phenol-lyase, a bacterial enzyme responsible for the synthesis of phenol from dietary tyrosine before it is metabolized into phenyl sulfate in the liver, reduces albuminuria in diabetic mice. Together, our results suggest that phenyl sulfate contributes to albuminuria and could be used as a disease marker and future therapeutic target in diabetic kidney disease., Diabetes is a major cause of kidney disease. Here Kikuchi et al. show that phenol sulfate, a gut microbiota-derived metabolite, is increased in diabetic kidney disease and contributes to the pathology by promoting kidney injury, suggesting phenyl sulfate could be used a marker and therapeutic target for the treatment of diabetic kidney disease.

Sporadic inclusion body myositis (sIBM) is the most common idiopathic inflammatory myopathy, and several reports have suggested that mitochondrial abnormalities are involved in its etiology. We recruited 9 sIBM patients and found significant histological changes and an elevation of growth differential factor 15 (GDF15), a marker of mitochondrial disease, strongly suggesting the involvement of mitochondrial dysfunction. Bioenergetic analysis of sIBM patient myoblasts revealed impaired mitochondrial function. Decreased ATP production, reduced mitochondrial size and reduced mitochondrial dynamics were also observed in sIBM myoblasts. Cell vulnerability to oxidative stress also suggested the existence of mitochondrial dysfunction. Mitochonic acid-5 (MA-5) increased the cellular ATP level, reduced mitochondrial ROS, and provided protection against sIBM myoblast death. MA-5 also improved the survival of sIBM skin fibroblasts as well as mitochondrial morphology and dynamics in these cells. The reduction in the gene expression levels of Opa1 and Drp1 was also reversed by MA-5, suggesting the modification of the fusion/fission process. These data suggest that MA-5 may provide an alternative therapeutic strategy for treating not only mitochondrial diseases but also sIBM.

Background Cardiorenal syndrome is a major cause of mortality in patients with chronic kidney disease (CKD). However, the involvement of detrimental humoral mediators in the pathogenesis of cardiorenal syndrome is still controversial. Trimethylamine-N-oxide (TMAO), a hepatic metabolic product of trimethylamine generated from dietary phosphatidylcholine or carnitine derived by the gut microbiota, has been linked directly with progression of cardiovascular disease and renal dysfunction. Thus, targeting TMAO may be a novel strategy for the prevention of cardiovascular disease and chronic kidney disease. Methods Linaclotide, a guanylate cyclase C agonist, was administered to adenine-induced renal failure (RF) mice and changes in renal function and levels of gut-derived uremic toxins, as well as the gut microbiota community, were analyzed using metabolomic and metagenomic methods to reveal its cardiorenal effect. Results Linaclotide decreased the plasma levels of TMAO at a clinically used low dose of 10 μg/kg in the adenine-induced RF mouse model. At a high concentration of 100 μg/kg, linaclotide clearly improved renal function and reduced the levels of various uremic toxins. A reduction in TMAO levels following linaclotide treatment was also observed in a choline-fed pro-atherosclerotic model. Linaclotide ameliorated renal inflammation and fibrosis and cardiac fibrosis, as well as decreased the expression of collagen I, transforming growth factor-β, galectin-3 (Gal-3) and ST2 genes. Plasma levels of Gal-3 and ST2 were also reduced. Because exposure of cardiomyocytes to TMAO increased fibronectin expression, these data suggest that linaclotide reduced the levels of TMAO and various uremic toxins and may result in not only renal, but also cardiac, fibrosis. F4/80-positive macrophages were abundant in small intestinal crypts in RF mice, and this increased expression was decreased by linaclotide. Reduced colonic claudin-1 levels were also restored by linaclotide, suggesting that linaclotide ameliorated the ‘leaky gut’ in RF mice. Metagenomic analysis revealed that the microbial order Clostridiales could be responsible for the change in TMAO levels. Conclusion Linaclotide reduced TMAO and uremic toxin levels and could be a powerful tool for the prevention and control of the cardiorenal syndrome by modification of the gut–cardio–renal axis.

Renal fibrosis is closely related to chronic inflammation and is under the control of epigenetic regulations. Because the signaling of transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) play key roles in progression of renal fibrosis, dual blockade of TGF-β1 and TNF-α is desired as its therapeutic approach. Here we screened small molecules showing anti-TNF-α activity in the compound library of indole derivatives. 11 out of 41 indole derivatives inhibited the TNF-α effect. Among them, Mitochonic Acid 35 (MA-35), 5-(3, 5-dimethoxybenzyloxy)-3-indoleacetic acid, showed the potent effect. The anti-TNF-α activity was mediated by inhibiting IκB kinase phosphorylation, which attenuated the LPS/GaIN-induced hepatic inflammation in the mice. Additionally, MA-35 concurrently showed an anti-TGF-β1 effect by inhibiting Smad3 phosphorylation, resulting in the downregulation of TGF-β1-induced fibrotic gene expression. In unilateral ureter obstructed mouse kidney, which is a renal fibrosis model, MA-35 attenuated renal inflammation and fibrosis with the downregulation of inflammatory cytokines and fibrotic gene expressions. Furthermore, MA-35 inhibited TGF-β1-induced H3K4me1 histone modification of the fibrotic gene promoter, leading to a decrease in the fibrotic gene expression. MA-35 affects multiple signaling pathways involved in the fibrosis and may recover epigenetic modification; therefore, it could possibly be a novel therapeutic drug for fibrosis.

α-Proteobacteria that can oxidize iodide (I(-)) to molecular iodine (I(2)) have only been isolated from iodide-rich natural and artificial environments, i.e., natural gas brine waters and seawaters supplemented with iodide, respectively. To understand the growth characteristics of such iodide-oxidizing bacteria (IOB) under iodide-rich environments, microcosms comprising natural seawater and 1 mM iodide were prepared, and the succession of microbial communities was monitored by culture-independent techniques. PCR-denaturing gradient gel electrophoresis and 16S rRNA gene sequence analysis showed that bacteria closely related with known IOB were predominant in the microcosms after several weeks of incubation. Quantitative PCR analysis targeting specific 16S rRNA gene regions of IOB showed that the relative abundance of IOB in the microcosms was 6-76% of the total bacterial population, whereas that in natural seawater was less than 1%. When 10(3) cells mL(-1) of IOB were inoculated into natural seawater supplemented with 0.1-1 mM iodide, significant growth (cell densities, 10(5)-10(6) cells mL(-1)) and I(2) production (6-32 μM) were observed. Interestingly, similar growth stimulation occurred when 12-44 μM of I(2) was added to seawater, instead of iodide. IOB were found to be more I(2) tolerant than the other heterotrophic bacteria in seawater. These results suggest that I(2) plays a key role in the growth stimulation of IOB in seawater. IOB could potentially attack other bacteria with I(2) to occupy their ecological niche in iodide-rich environments.

Iodide-oxidizing bacteria (IOB), which oxidize iodide (I-) to molecular iodine (I2), were isolated from iodide-rich (63 microM to 1.2 mM) natural gas brine waters collected from several locations. Agar media containing iodide and starch were prepared, and brine waters were spread directly on the media. The IOB, which appeared as purple colonies, were obtained from 28 of the 44 brine waters. The population sizes of IOB in the brines were 10(2) to 10(5) colony-forming units (CFU) mL(-1). However, IOB were not detected in natural seawaters and terrestrial soils (fewer than 10 CFU mL(-1) and 10(2) CFU g wet weight of soils(-1), respectively). Interestingly, after the enrichment with 1 mM iodide, IOB were found in 6 of the 8 seawaters with population sizes of 10(3) to 10(5) CFU mL(-1). 16S rDNA sequencing and phylogenetic analyses showed that the IOB strains are divided into two groups within the alpha-subclass of the Proteobacteria. One of the groups was phylogenetically most closely related to Roseovarius tolerans with sequence similarities between 94% and 98%. The other group was most closely related to Rhodothalassium salexigens, although the sequence similarities were relatively low (89% to 91%). The iodide-oxidizing reaction by IOB was mediated by an extracellular enzyme protein that requires oxygen. Radiotracer experiments showed that IOB produce not only I2 but also volatile organic iodine, which were identified as diiodomethane (CH2I2) and chloroiodomethane (CH2ClI). These results indicate that at least two types of IOB are distributed in the environment, and that they are preferentially isolated in environments in which iodide levels are very high. It is possible that IOB oxidize iodide in the natural environment, and they could significantly contribute to the biogeochemical cycling of iodine.