Presentation_1_Nicotinamide adenine dinucleotide supplementation drives gut microbiota variation in Alzheimer’s mouse model.pdf

Alzheimer’s disease (AD) is the most common neurodegenerative disease. Growing evidence suggests an important role for gut dysbiosis and gut microbiota-host interactions in aging and neurodegeneration. Our previous works have demonstrated that supplementation with the nicotinamide adenine dinucleotide (NAD+) precursor, nicotinamide riboside (NR), reduced the brain features of AD, including neuroinflammation, deoxyribonucleic acid (DNA) damage, synaptic dysfunction, and cognitive impairment. However, the impact of NR administration on the intestinal microbiota of AD remains unknown. In this study, we investigated the relationship between gut microbiota and NR treatment in APP/PS1 transgenic (AD) mice. Compared with wild type (WT) mice, the gut microbiota diversity in AD mice was lower and the microbiota composition and enterotype were significantly different. Moreover, there were gender differences in gut microbiome between female and male AD mice. After supplementation with NR for 8 weeks, the decreased diversity and perturbated microbial compositions were normalized in AD mice. This included the species Oscillospira, Butyricicoccus, Desulfovibrio, Bifidobacterium, Olsenella, Adlercreutzia, Bacteroides, Akkermansia, and Lactobacillus. Our results indicate an interplay between NR and host-microbiota in APP/PS1 mice, suggesting that the effect of NR on gut dysbiosis may be an important component in its therapeutic functions in AD.</p

γ-H2AX foci/cell in human leukapheresis-derived mononuclear cells for hypertensive and non-hypertensive patients.

<p>Mononuclear cells from patients with hypertension age 57 and older show a significant (<i>p</i> = 0.037, adjusted for age and sex) increase of 30% of γ-H2AX foci/cell compared to the cells from non-hypertensive patients in the same age group.</p

γ-H2AX foci/cell in human leukapheresis-derived mononuclear cells, stratified by disease subgroups which contribute to oxidative stress and/or DNA damage (with the exception of benign prostatic hyperplasia).

<p>Average γ-H2AX foci/cell is shown for each disease subgroup and significance is adjusted for age and sex. Vitamin D deficient patients show an increase of 41% of γ-H2AX foci/cell compared to the cells from those without known vitamin D deficiency (<i>p</i> = 0.023). There is also a similar strong trend (30–39% increase in average number of γ-H2AX foci/cell, that does not quite reach significance; <i>p</i> values <0.10) in cells derived from patients with cataract formation and sleep apnea. Patients with cancer irradiation treatment show an increase in H2AX foci/cell (41%) but did not reach statistical significance (<i>p</i> = 0.23). Patients with cancer (Basal cell carcinoma or visceral cancer which includes prostate and colon cancer) showed no significant differences. Patients with benign prostatic hyperplasia also did not show any significant differences, as expected.</p>*<p>one patient had both a visceral cancer and a basal cell carcinoma.</p>#<p>adjusted for age.</p

γ-H2AX foci in human leukapheresis-derived mononuclear cells and transformed lymphocytes.

<p>(<b>A</b>) Human leukapheresis-derived mononuclear cells, stained for γ-H2AX foci. Image post preset automated algorithm for image analysis using Adobe Photoshop, version 7.0. Preset automated algorithm for image analysis consists of: ‘auto contrast,’ ‘auto levels,’ ‘desaturate,’ ‘invert.’ Without DAPI overlay, γ-H2AX foci which fell within the area of the nucleus were easier to identify and count. (<b>B</b>) Human leukapheresis-derived mononuclear cells, stained for γ-H2AX foci and overlaid with DAPI stained nuclear DNA antibody. Image post preset as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045728#pone-0045728-g001" target="_blank">Figure 1A</a>. With DAPI overlay, γ-H2AX foci were more difficult to identify and count. (<b>C–E</b>) γ-H2AX foci in human transformed lymphocytes, Cytocentrifugation at various speeds before fixation. C. 200 rpm, D. 350 rpm, E. 500 rpm. Severity of DNA damage increases with higher G force settings.</p

Box plots of γ-H2AX foci/cell in mononuclear cells by age for patients with vitamin D deficiency and hypertension.

<p>(<b>A</b>) Box plot of γ-H2AX foci/cell in human leukapheresis-derived mononuclear cells by age for patients with vitamin deficiency compared to those with no known vitamin D deficiency. (<b>B</b>) Box plot of γ-H2AX foci/cell in human leukapheresis-derived mononuclear cells by age for hypertensive patients vs. non-hypertensive patients. (<b>C</b>) Box plot of γ-H2AX foci/cell in human leukapheresis-derived mononuclear cells by age for hypertensive patients vs. non-hypertensive patients, age ≥57 y/o. The top of each box in the box plots indicates the 75^th percentile, the bottom of each box indicates the 25^th percentile and the bar inside the box is the median. The whiskers extend out to the most extreme data point that is at most 1.5 times the interquartile range above the third quartile or below the first quartile. The circle in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045728#pone-0045728-g003" target="_blank">Figure 3</a> (A) indicates a result from a patient above this range.</p

Theoretical vs. actual pattern for average number of γ-H2AX foci/cell by age.

<p>Expected increase of the average number of γ-H2AX foci/cell for each age group would theoretically mimic the prevalence of disease for that age group (shown by arrows) given that healthier patients have lower counts and morbid patients have higher counts. Solid line models actual patterns for Sedelnikova <i>et al. </i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045728#pone.0045728-Sedelnikova3" target="_blank">[11]</a> and the present study. The dashed line represents theoretical averages if a cross-section for an entire age group for a given population could be measured. Many patients, however, with morbidities such as metastatic cancer, dementia, heart disease and diabetes may not volunteer, be available or be eligible for sampling studies thus possibly skewing results toward healthier indices.</p

Distribution of γ-H2AX foci/cell in human leukapheresis-derived mononuclear cells by age.

<p>(<b>A</b>) γ-H2AX foci in human leukapheresis-derived mononuclear cells, stratified by age subgroups. Average γ-H2AX foci/cell is shown for each age subgroup. (<b>B</b>) Scatter plot of γ-H2AX foci/cell in human leukapheresis-derived mononuclear cells by age. Dotted line is best fit showing change-point (age 57) as determined by piecewise linear regression.</p

Scatterplot of γ-H2AX foci/cell in mononuclear cells by age for patients with and without hypertension.

<p>Solid circles indicate patients with hypertension; hollow circles indicate those without hypertension. Solid line indicates best fit line for hypertension patients age 57 and over. Dashed line indicates best fit line for non-hypertensive patients age 57 and over. Light line indicates regression curve for all patients.</p

Identification of a Chemical That Inhibits the Mycobacterial UvrABC Complex in Nucleotide Excision Repair

Bacterial DNA can be damaged by reactive nitrogen and oxygen intermediates (RNI and ROI) generated by host immunity, as well as by antibiotics that trigger bacterial production of ROI. Thus a pathogen’s ability to repair its DNA may be important for persistent infection. A prominent role for nucleotide excision repair (NER) in disease caused by <i>Mycobacterium tuberculosis</i> (Mtb) was suggested by attenuation of <i>uvrB</i>-deficient Mtb in mice. However, it was unknown if Mtb’s Uvr proteins could execute NER. Here we report that recombinant UvrA, UvrB, and UvrC from Mtb collectively bound and cleaved plasmid DNA exposed to ultraviolet (UV) irradiation or peroxynitrite. We used the DNA incision assay to test the mechanism of action of compounds identified in a high-throughput screen for their ability to delay recovery of <i>M. smegmatis</i> from UV irradiation. 2-(5-Amino-1,3,4-thiadiazol-2-ylbenzo[<i>f</i>]chromen-3-one) (ATBC) but not several closely related compounds inhibited cleavage of damaged DNA by UvrA, UvrB, and UvrC without intercalating in DNA and impaired recovery of <i>M. smegmatis</i> from UV irradiation. ATBC did not affect bacterial growth in the absence of UV exposure, nor did it exacerbate the growth defect of UV-irradiated mycobacteria that lacked <i>uvrB</i>. Thus, ATBC appears to be a cell-penetrant, selective inhibitor of mycobacterial NER. Chemical inhibitors of NER may facilitate studies of the role of NER in prokaryotic pathobiology