Ubiquitination of DNA Damage-Stalled RNAPII Promotes Transcription-Coupled Repair.

Transcription-coupled nucleotide excision repair (TC-NER) is initiated by the stalling of elongating RNA polymerase II (RNAPIIo) at DNA lesions. The ubiquitination of RNAPIIo in response to DNA damage is an evolutionarily conserved event, but its function in mammals is unknown. Here, we identified a single DNA damage-induced ubiquitination site in RNAPII at RPB1-K1268, which regulates transcription recovery and DNA damage resistance. Mechanistically, RPB1-K1268 ubiquitination stimulates the association of the core-TFIIH complex with stalled RNAPIIo through a transfer mechanism that also involves UVSSA-K414 ubiquitination. We developed a strand-specific ChIP-seq method, which revealed RPB1-K1268 ubiquitination is important for repair and the resolution of transcriptional bottlenecks at DNA lesions. Finally, RPB1-K1268R knockin mice displayed a short life-span, premature aging, and neurodegeneration. Our results reveal RNAPII ubiquitination provides a two-tier protection mechanism by activating TC-NER and, in parallel, the processing of DNA damage-stalled RNAPIIo, which together prevent prolonged transcription arrest and protect against neurodegeneration.

Iodine-containing ointment-induced hypothyroidism in a patient with anorexia nervosa and sacral decubitus ulcer: a case report with literature review.

We present a case of a 58-year-old woman with anorexia nervosa and a sacral decubitus ulcer who developed hypothyroidism because of an iodine-containing ointment. Considering the absence of autoimmune thyroid diseases, the development of hypothyroidism after the use of an iodine-containing ointment, and the recovery of thyroid function after the discontinuation of the ointment, we presumed that her hypothyroidism was induced by the iodine-containing ointment. Although the hypothyroidism improved after discontinuing the iodine-containing ointment, she developed aspiration pneumonia and required long-term hospitalization. Many patients with autoimmune thyroid diseases develop hypothyroidism after excessive iodine intake. However, anorexia nervosa may have exacerbated the iodine-induced hypothyroidism in our patient. To the best of our knowledge, no previous study has reported a case of hypothyroidism caused by iodine-containing ointment in a patient with anorexia nervosa. Hence, physicians must pay careful attention to a patient's background factors to ensure the early diagnosis of hypothyroidism due to iodine-containing ointments.

Cellular zinc is required for intestinal epithelial barrier maintenance via the regulation of claudin-3 and occludin expression.

Intracellular zinc is required for a variety of cell functions, but its precise roles in the maintenance of the intestinal tight junction (TJ) barrier remain unclear. The present study investigated the essential roles of intracellular zinc in the preservation of intestinal TJ integrity and the underlying molecular mechanisms. Depletion of intracellular zinc in both intestinal Caco-2 cells and mouse colons through the application of a cell-permeable zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) induced a disruption of the TJ barrier, as indicated by increased FITC-labeled dextran flux and decreased transepithelial electrical resistance. The TPEN-induced TJ disruption is associated with downregulation of two TJ proteins, occludin and claudin-3. Biotinylation of cell surface proteins revealed that the zinc depletion induced the proteolysis of occludin but not claudin-3. Occludin proteolysis was sensitive to the inhibition of calpain activity, and increased calpain activity was observed in the zinc-depleted cells. Although quantitative PCR analysis and promoter reporter assay have demonstrated that the zinc depletion-induced claudin-3 downregulation occurred at transcriptional levels, a site-directed mutation in the egr1 binding site in the claudin-3 promoter sequence induced loss of both the basal promoter activity and the TPEN-induced decreases. Reduced egr1 expression by a specific siRNA also inhibited claudin-3 expression and transepithelial electrical resistance maintenance in cells. This study shows that intracellular zinc has an essential role in the maintenance of the intestinal epithelial TJ barrier through regulation of occludin proteolysis and claudin-3 transcription.

Nivolumab, an Anti-Programmed Cell Death-1 Antibody, Induces Fulminant Type 1 Diabetes.

Programmed cell death-1 (PD-1), an immunoreceptor, is located on T cells and pro-B cells and interacts with its ligands to inhibit T cell activation and proliferation, thereby promoting immunological self-tolerance. Nivolumab, an anti-PD1 antibody, blocks PD-1 and can restore anticancer immune responses by abrogating PD-1 pathway-mediated T-cell inhibition. Autoimmune adverse events are expected with PD-1 therapy. Fulminant type 1 diabetes is the subtype of type 1 diabetes. The clinical feature is the extremely rapid progression of hyperglycemia and ketoacidosis. Here we describe a 66-year-old woman with advanced melanoma who was treated with nivolumab. After 4 months and six doses of the medicine, the patient was admitted to the hospital with complaints of nausea and vomiting. The laboratory data showed ketonuria, hyperglycemia (531 mg/dl), high anion gap metabolic acidosis, HbA1c (7.3%), and absence of insulin-secreting capacity. These data are compatible with the criteria of fulminant type 1 diabetes. The patient was diagnosed with diabetic ketoacidosis because of fulminant type 1 diabetes. The findings of this case indicated that nivolumab can cause fulminant type 1 diabetes. Diabetic ketoacidosis due to fulminant type 1 diabetes is potentially fatal condition. Thus, diabetic ketoacidosis due to fulminant type 1 diabetes should be considered in the differential diagnosis when patients treated with nivolumab complain of gastrointestinal symptoms.

Degradation and synthesis of ß-glucans by a Magnaporthe oryzae endotransglucosylase, a member of the glycoside hydrolase 7 family.

BACKGROUND: Plant pathogens secrete enzymes that degrade plant cell walls to enhance infection and nutrient acquisition. RESULTS: A novel endotransglucosylase catalyzes cleavage and transfer of ß-glucans and decreases the physical strength of plant cell walls. CONCLUSION: Endotransglucosylation causes depolymerization and polymerization of ß-glucans, depending on substrate molecular size. SIGNIFICANCE: Enzymatic degradation of plant cell walls is required for wall loosening, which enhances pathogen invasion. A Magnaporthe oryzae enzyme, which was encoded by the Mocel7B gene, was predicted to act on 1,3-1,4-ß-glucan degradation and transglycosylation reaction of cellotriose after partial purification from a culture filtrate of M. oryzae cells, followed by liquid chromatography-tandem mass spectrometry. A recombinant MoCel7B prepared by overexpression in M. oryzae exhibited endo-typical depolymerization of polysaccharides containing ß-1,4-linkages, in which 1,3-1,4-ß-glucan was the best substrate. When cellooligosaccharides were used as the substrate, the recombinant enzyme generated reaction products with both shorter and longer chain lengths than the substrate. In addition, incorporation of glucose and various oligosaccharides including sulforhodamine-conjugated cellobiose, laminarioligosaccharides, gentiobiose, xylobiose, mannobiose, and xyloglucan nonasaccharide into ß-1,4-linked glucans were observed after incubation with the enzyme. These results indicate that the recombinant enzyme acts as an endotransglucosylase (ETG) that cleaves the glycosidic bond of ß-1,4-glucan as a donor substrate and transfers the cleaved glucan chain to another molecule functioning as an acceptor substrate. Furthermore, ETG treatment caused greater extension of heat-treated wheat coleoptiles. The result suggests that ETG functions to induce wall loosening by cleaving the 1,3-1,4-ß-glucan tethers of plant cell walls. On the other hand, use of cellohexaose as a substrate for ETG resulted in the production of cellulose II with a maximum length (degree of polymerization) of 26 glucose units. Thus, ETG functions to depolymerize and polymerize ß-glucans, depending on the size of the acceptor substrate.

Recurrent hyperglycemic hyperosmolar state after re-administration of dose-reduced ceritinib, an anaplastic lymphoma kinase inhibitor.

Ceritinib is a second-generation anaplastic lymphoma kinase (ALK) inhibitor with clinical activity in crizotinib-resistant ALK-positive non-small cell lung cancer and in treatment-naïve ALK-positive disease. Hyperglycemia is a known adverse event, but the mechanism by which ceritinib causes hyperglycemia is unknown, and whether ceritinib causes hyperglycemic emergencies is unclear. Here, we report the case of a patient with a hyperglycemic hyperosmolar state (HHS) recurrence after the re-administration of dose-reduced ceritinib. A 78-year-old man with type 2 diabetes diagnosed as having advanced lung adenocarcinoma had been treated with alogliptin (25 mg/day) for the diabetes and with ceritinib for the lung cancer. After 28 days of ceritinib administration, he was admitted to our hospital due to HHS. His blood glucose level improved with insulin therapy after discontinuation of the ceritinib. He then received re-administration with a decreased ceritinib dose while maintaining the insulin treatment to control his blood glucose, but his HHS recurred. We discontinued the ceritinib for other side effects and noticed the HHS disappeared. Our findings suggest that ceritinib can cause HHS and that HHS may recur even after dose reductions.

Severe and Recurrent Hypoglycemia Caused by Garenoxacin in a Patient not Taking Hypoglycemic Drugs.

Quinolones are known to induce hypoglycemia, although there is no written report of garenoxacin-induced hypoglycemia. We herein report a case of garenoxacin-induced hypoglycemia in a patient not taking hypoglycemic drugs. An 89-year-old Japanese woman with type 2 diabetes and chronic renal insufficiency requiring hemodialysis was admitted to the emergency department in a comatose state. Her serum glucose measured 1 mg/dL on arrival. The patient had not taken any hypoglycemic drugs recently and had never experienced a hypoglycemic episode. She had received a four-day course of garenoxacin treatment before the emergency admission. Clinicians should therefore recognize the potential risk of hypoglycemia during garenoxacin therapy.

Salt-inducible kinase 3 regulates the mammalian circadian clock by destabilizing PER2 protein.

Salt-inducible kinase 3 (SIK3) plays a crucial role in various aspects of metabolism. In the course of investigating metabolic defects in Sik3-deficient mice (Sik3-/-), we observed that circadian rhythmicity of the metabolisms was phase-delayed. Sik3-/- mice also exhibited other circadian abnormalities, including lengthening of the period, impaired entrainment to the light-dark cycle, phase variation in locomotor activities, and aberrant physiological rhythms. Ex vivo suprachiasmatic nucleus slices from Sik3-/- mice exhibited destabilized and desynchronized molecular rhythms among individual neurons. In cultured cells, Sik3-knockdown resulted in abnormal bioluminescence rhythms. Expression levels of PER2, a clock protein, were elevated in Sik3-knockdown cells but down-regulated in Sik3-overexpressing cells, which could be attributed to a phosphorylation-dependent decrease in PER2 protein stability. This was further confirmed by PER2 accumulation in the Sik3-/- fibroblasts and liver. Collectively, SIK3 plays key roles in circadian rhythms by facilitating phosphorylation-dependent PER2 destabilization, either directly or indirectly.

A new mouse allele of glutamate receptor delta 2 with cerebellar atrophy and progressive ataxia.

Spinocerebellar degenerations (SCDs) are a large class of sporadic or hereditary neurodegenerative disorders characterized by progressive motion defects and degenerative changes in the cerebellum and other parts of the CNS. Here we report the identification and establishment from a C57BL/6J mouse colony of a novel mouse line developing spontaneous progressive ataxia, which we refer to as ts3. Frequency of the phenotypic expression was consistent with an autosomal recessive Mendelian trait of inheritance, suggesting that a single gene mutation is responsible for the ataxic phenotype of this line. The onset of ataxia was observed at about three weeks of age, which slowly progressed until the hind limbs became entirely paralyzed in many cases. Micro-MRI study revealed significant cerebellar atrophy in all the ataxic mice, although individual variations were observed. Detailed histological analyses demonstrated significant atrophy of the anterior folia with reduced granule cells (GC) and abnormal morphology of cerebellar Purkinje cells (PC). Study by ultra-high voltage electron microscopy (UHVEM) further indicated aberrant morphology of PC dendrites and their spines, suggesting both morphological and functional abnormalities of the PC in the mutants. Immunohistochemical studies also revealed defects in parallel fiber (PF)-PC synapse formation and abnormal distal extension of climbing fibers (CF). Based on the phenotypic similarities of the ts3 mutant with other known ataxic mutants, we performed immunohistological analyses and found that expression levels of two genes and their products, glutamate receptor delta2 (grid2) and its ligand, cerebellin1 (Cbln1), are significantly reduced or undetectable. Finally, we sequenced the candidate genes and detected a large deletion in the coding region of the grid2 gene. Our present study suggests that ts3 is a new allele of the grid2 gene, which causes similar but different phenotypes as compared to other grid2 mutants.