Changes in histopathology and heteroplasmy rates over 8 years and effectiveness of taurine supplementation in a patient with mitochondrial nephropathy caused by MT-TL1 mutation: A case report.

The m.3243A > G mutation in the mitochondrially encoded tRNA leucine 1 (MT-TL1) gene is known to cause mitochondrial nephropathy. However, its long-term effects of the m.3243A > G mutation on renal histopathology or heteroplasmy rates remain unknown. Here we present the case of a female patient who underwent renal biopsy at 34 years of age to investigate the reason for a low estimated glomerular filtration rate (eGFR) of 47.9 mL/min/1.73 m2. Light microscopy revealed nephrosclerosis with granular swollen epithelial cells (GSECs) in the renal tubules. Genetic testing revealed the m.3243A > G mutation in the MT-TL1 gene. Over a follow-up period of 8 years, the eGFR declined at a rate of 1.50 mL/min/1.73 m2/year. A second renal biopsy was performed at the age of 42 years; the patient's glomerular sclerosis rate had increased from 45.5% to 63.2%, and the frequency of GSECs in the collecting ducts had increased from 5.8% to 20.8%. Furthermore, the heteroplasmy rate in blood cells and urinary sediment cells increased from 9% to 20% and 20% to 53%, respectively. Taurine therapy was initiated just after the second kidney biopsy. To date, after approximately 3 years of taurine administration, the rate of eGFR decline has markedly decreased to 0.26 mL/min/1.73 m2/year. This experience suggests that an increased heteroplasmy rate may be associated with the progression of mitochondrial nephropathy caused by MT-TL1 mutation. Furthermore, our case is the first to suggest the effectiveness of taurine for mitochondrial nephropathy caused by the m.3243A > G mutation in the MT-TL1 gene.

Biallelic IARS Mutations Cause Growth Retardation with Prenatal Onset, Intellectual Disability, Muscular Hypotonia, and Infantile Hepatopathy.

tRNA synthetase deficiencies are a growing group of genetic diseases associated with tissue-specific, mostly neurological, phenotypes. In cattle, cytosolic isoleucyl-tRNA synthetase (IARS) missense mutations cause hereditary weak calf syndrome. Exome sequencing in three unrelated individuals with severe prenatal-onset growth retardation, intellectual disability, and muscular hypotonia revealed biallelic mutations in IARS. Studies in yeast confirmed the pathogenicity of identified mutations. Two of the individuals had infantile hepatopathy with fibrosis and steatosis, leading in one to liver failure in the course of infections. Zinc deficiency was present in all affected individuals and supplementation with zinc showed a beneficial effect on growth in one.

Curdlan induces DC-mediated Th17 polarization via Jagged1 activation in human dendritic cells.

BACKGROUND: Th17-inducing activity is carried by certain polysaccharides such as beta-glucan derived from Candia albicans. Our previous studies have shown that Th1- and Th2-inducing activities can be qualitatively evaluated by the expression patterns of Notch ligand isoforms, using human monocyte-derived dendritic cells (Mo-DCs) and some leukemic cell lines such as THP-1. The association of Th17-inducing activities with Notch ligand expression patterns has been unclear. METHODS: Mo-DCs from healthy volunteers were co-cultured with HLA-DR-nonshared allogeneic CD4+ naïve T cells to induce a mixed lymphocyte reaction, in the presence of adjuvants, such as curdlan. Culture supernatants were assayed for IFNgamma, IL-5 and IL-17 by an enzyme-linked immunosorbent assay (ELISA). Notch ligand expression on Mo-DCs and THP-1 cells was evaluated by using RT-PCR. RESULTS: The present study shows that curdlan, one of the beta-glucans, has the ability to induce DC-mediated Th17 differentiation. It is also interesting to note that Jagged1 mRNA in Mo-DCs and THP-1 cells is up-regulated by curdlan. Furthermore, polyclonal anti-Jagged1 antibody inhibited such DC-mediated Th17 differentiation. CONCLUSIONS: This study suggests that curdlan induces human DC-mediated Th17 polarization via Jagged1 activation in DCs.