Daniel Aires

Ncb5or deficiency increases fatty acid catabolism and oxidative stress

The endoplasmic reticulum-associated NADH cytochrome b5 oxidoreductase (Ncb5or) is widely distributed in animal tissues. Ncb5or−/− mice develop diabetes at age 7 weeks and have increased susceptibility to the diabetogenic oxidant streptozotocin. Ncb5or deficiency also results in lipoatrophy and increased hepatocyte sensitivity to cytotoxic effects of saturated fatty acids. Here we investigate the mechanisms of these phenomena in prediabetic Ncb5or−/− mice and find that, despite increased rates of fatty acid uptake and synthesis and higher stearoyl-CoA desaturase (SCD) expression, Ncb5or−/− liver accumulates less triacylglycerol (TAG) than wild type (WT). Increased fatty acid catabolism and oxidative stress are evident in Ncb5or−/− hepatocytes and reflect increased mitochondrial content, peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) expression, fatty acid oxidation rates, oxidative stress response gene expression, and oxidized glutathione content. Ncb5or−/− hepatocytes readily incorporate exogenous fatty acids into TAG but accumulate more free fatty acids (FFA) and have greater palmitate-induced oxidative stress responses and cell death than WT, all of which are alleviated by co-incubation with oleate via TAG channeling. A high fat diet rich in palmitate and oleate stimulates both lipogenesis and fatty acid catabolism in Ncb5or−/− liver, resulting in TAG levels similar to WT but increased intracellular FFA accumulation. Hepatic SCD-specific activity is lower in Ncb5or−/− than in WT mice, although Ncb5or−/− liver has a greater increase in Scd1 mRNA and protein levels. Together, these findings suggest that increased FFA accumulation and catabolism and oxidative stress are major consequences of Ncb5or deficiency in liver.

Impact of Molecular Weight on Lymphatic Drainage of a Biopolymer-Based Imaging Agent

New lymphatic imaging technologies are needed to better assess immune function and cancer progression and treatment. Lymphatic uptake depends mainly on particle size (10–100 nm) and charge. The size of carriers for imaging and drug delivery can be optimized to maximize lymphatic uptake, localize chemotherapy to lymphatic metastases, and enable visualization of treatment deposition. Toward this end, female BALB/c mice were injected subcutaneously in the hind footpad or forearm with a series of six different molecular weight hyaluronan (HA) near-infrared dye (HA-IR820) conjugates (ca. 5–200 nm). Mice were imaged using whole body fluorescent imaging over two weeks. HA-IR820 fluorescence was clearly visualized in the draining lymphatic capillaries, and in the popliteal and iliac or axillary lymph nodes. The 74-kDa HA-IR820 had the largest lymph node area-under-the-curve. In contrast to prior reports, mice bearing limb tumors exhibited three-fold longer retention of 74-kDa HA-IR820 in the popliteal node compared to mice without tumors. HA conjugate kinetics and disposition can be specifically tailored by altering their molecular weight. The specific lymphatic uptake and increased nodal retention of HA conjugates indicate significant potential for development as a natural biopolymer for intralymphatic drug delivery and imaging.

Glycolysis–respiration relationships in a neuroblastoma cell line

BACKGROUND Although some reciprocal glycolysis-respiration relationships are well recognized, the relationship between reduced glycolysis flux and mitochondrial respiration has not been critically characterized. METHODS We concomitantly measured the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) of SH-SY5Y neuroblastoma cells under free and restricted glycolysis flux conditions. RESULTS Under conditions of fixed energy demand ECAR and OCR values showed a reciprocal relationship. In addition to observing an expected Crabtree effect in which increasing glucose availability raised the ECAR and reduced the OCR, a novel reciprocal relationship was documented in which reducing the ECAR via glucose deprivation or glycolysis inhibition increased the OCR. Substituting galactose for glucose, which reduces net glycolysis ATP yield without blocking glycolysis flux, similarly reduced the ECAR and increased the OCR. We further determined how reduced ECAR conditions affect proteins that associate with energy sensing and energy response pathways. ERK phosphorylation, SIRT1, and HIF1a decreased while AKT, p38, and AMPK phosphorylation increased. CONCLUSIONS These data document a novel intracellular glycolysis-respiration effect in which restricting glycolysis flux increases mitochondrial respiration. GENERAL SIGNIFICANCE Since this effect can be used to manipulate cell bioenergetic infrastructures, this particular glycolysis-respiration effect can practically inform the development of new mitochondrial medicine approaches.

Treatment of dermatosis papulosa nigra with a 1064 nm Nd:YAG laser: Report of two cases

Dermatosis papulosa nigra (DPN) is a chronic skin condition characterized by verrucous hyperpigmented papules on the face, neck and upper trunk in African American patients. The lesions are more common in females and in older patients. Although the lesions are benign, treatment is often sought for cosmetic reasons. We report two cases of patients with facial DPN who achieved an excellent cosmetic result following a single treatment with a long‐pulsed 1064 nm Nd:YAG laser. We suggest this modality for consideration in treating patients with DPN.

Development of Diabetes in Lean Ncb5or-Null Mice is Associated with Manifestations of Endoplasmic Reticulum and Oxidative Stress in Beta Cells

NADH-cytochrome b5 oxidoreductase (Ncb5or) is an endoplasmic reticulum (ER)-associated redox enzyme involved in fatty acid metabolism, and phenotypic abnormalities of Ncb5or(-/-) mice include diabetes and lipoatrophy. These mice are lean and insulin-sensitive but become hyperglycemic at age 7 weeks as a result of β-cell dysfunction and loss. Here we examine early cellular and molecular events associated with manifestations of β-cell defects in Ncb5or(-/-) mice. We observe lower islet β-cell content in pancreata at age 4 weeks and prominent ER distention in β-cells by age 5 weeks. Ultrastructural changes progress rapidly in severity from age 5 to 6 weeks, and their frequency rises from 10% of β-cells at 5 weeks to 33% at 6 weeks. These changes correlate temporally with the onset of diabetes. ER stress responses and lipid load in Ncb5or(-/-) β-cells were assessed with isolated islets from mice at age 5 weeks. Expression levels of the stress marker protein Grp78/BiP and of phosphorylated eIF2α protein were found to be reduced, although their transcript levels did not decline. This pattern stands in contrast to the canonical unfolded protein response. Ncb5or(-/-) β-cells also accumulated higher intracellular levels of palmitate and other free fatty acids and exhibited greater reactive oxygen species production than wild-type cells. An alloxan-susceptible genetic background was found to confer accelerated onset of diabetes in Ncb5or(-/-) mice. These findings provide the first direct evidence that manifestations of diabetes in lean Ncb5or(-/-) mice involve saturated free fatty acid overload of β-cells and ER and oxidative stress responses.

Lymphatic trafficking kinetics and near-infrared imaging using star polymer architectures with controlled anionic character

Targeted lymphatic delivery of nanoparticles for drug delivery and imaging is primarily dependent on size and charge. Prior studies have observed increased lymphatic uptake and retentions of over 48 h for negatively charged particles compared to neutral and positively charged particles. We have developed new polymeric materials that extend retention over a more pharmaceutically relevant 7-day period. We used whole body fluorescence imaging to observe in mice the lymphatic trafficking of a series of anionic star poly-(6-O-methacryloyl-D-galactose) polymer-NIR dye (IR820) conjugates. The anionic charge of polymers was increased by modifying galactose moieties in the star polymers with succinic anhydride. Increasing anionic nature was associated with enhanced lymphatic uptake up to a zeta potential of ca.-40 mV; further negative charge did not affect lymphatic uptake. Compared to the 20% acid-conjugate, the 40-90% acid-star-polymer conjugates exhibited a 2.5- to 3.5-fold increase in lymphatic uptake in both the popliteal and iliac nodes. The polymer conjugates exhibited node half-lives of 2-20 h in the popliteal nodes and 19-114 h in the deeper iliac nodes. These polymer conjugates can deliver drugs or imaging agents with rapid lymphatic uptake and prolonged deep-nodal retention; thus they may provide a useful vehicle for sustained intralymphatic drug delivery with low toxicity.

Consumption of polyphenol plants may slow aging and associated diseases.

Slowing aging is a widely shared goal. Plant-derived polyphenols, which are found in commonly consumed food plants such as tea, cocoa, blueberry and grape, have been proposed to have many health benefits, including slowing aging. In-vivo studies have demonstrated the lifespan-extending ability of six polyphenol-containing plants. These include five widely consumed foods (tea, blueberry, cocoa, apple, pomegranate) and a flower commonly used as a folk medicine (betony). These and multiple other plant polyphenols have been shown to have beneficial effects on aging-associated changes across a variety of organisms from worm and fly to rodent and human.

Potentiation of dietary restriction-induced lifespan extension by polyphenols

Dietary restriction (DR) extends lifespan across multiple species including mouse. Antioxidant plant extracts rich in polyphenols have also been shown to increase lifespan. We hypothesized that polyphenols might potentiate DR-induced lifespan extension. Twenty week old C57BL/6 mice were placed on one of three diets: continuous feeding (control), alternate day chow (Intermittent fed, IF), or IF supplemented with polyphenol antioxidants (PAO) from blueberry, pomegranate, and green tea extracts (IF+PAO). Both IF and IF+PAO groups outlived the control group and the IF+PAO group outlived the IF group (all p<0.001). In the brain, IF induced the expression of inflammatory genes and p38 MAPK phosphorylation, while the addition of PAO reduced brain inflammatory gene expression and p38 MAPK phosphorylation. Our data indicate that while IF overall promotes longevity, some aspects of IF-induced stress may paradoxically lessen this effect. Polyphenol compounds, in turn, may potentiate IF-induced longevity by minimizing specific components of IF-induced cell stress.

Alternate day fasting impacts the brain insulin-signaling pathway of young adult male C57BL/6 mice

J. Neurochem. (2011) 117, 154–163.

Successful Treatment with Injected Hyaluronic Acid in a Patient with Lip Asymmetry after Surgical Correction of Cleft Lip

BACKGROUND Surgical repair of cleft lip, while correcting deformity and dysfunction, may leave residual cosmetic imperfections. The resultant asymmetry and low volume of the upper lip can be addressed surgically and via less invasive methods. OBJECTIVE We present the first reported use of injectable hyaluronic acid to correct the characteristic lip asymmetry and poor volume after surgical repair of a cleft lip. METHODS AND MATERIALS Using injectable hyaluronic acid, we treated the patients upper lip to restore symmetry and achieve an augmented volume. RESULTS We obtained a symmetric correction and aesthetically pleasing volume augmentation in the affected lip. These results lasted approximately 4 months. CONCLUSION Using a temporary, alloplastic, injectable soft tissue filler such as hyaluronic acid satisfactorily achieves correction of asymmetry and low volume in a surgically repaired cleft lip. For patients who have endured multiple corrective surgeries, this is a novel and less invasive way to improve their cosmetic concerns.