16 research outputs found
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Flavonoid Apigenin Is an Inhibitor of the NAD+ase CD38: Implications for Cellular NAD+ Metabolism, Protein Acetylation, and Treatment of Metabolic Syndrome
Metabolic syndrome is a growing health problem worldwide. It is therefore imperative to develop new strategies to treat this pathology. In the past years, the manipulation of NAD+ metabolism has emerged as a plausible strategy to ameliorate metabolic syndrome. In particular, an increase in cellular NAD+ levels has beneficial effects, likely because of the activation of sirtuins. Previously, we reported that CD38 is the primary NAD+ase in mammals. Moreover, CD38 knockout mice have higher NAD+ levels and are protected against obesity and metabolic syndrome. Here, we show that CD38 regulates global protein acetylation through changes in NAD+ levels and sirtuin activity. In addition, we characterize two CD38 inhibitors: quercetin and apigenin. We show that pharmacological inhibition of CD38 results in higher intracellular NAD+ levels and that treatment of cell cultures with apigenin decreases global acetylation as well as the acetylation of p53 and RelA-p65. Finally, apigenin administration to obese mice increases NAD+ levels, decreases global protein acetylation, and improves several aspects of glucose and lipid homeostasis. Our results show that CD38 is a novel pharmacological target to treat metabolic diseases via NAD+-dependent pathways
Connectivity-guided intermittent theta burst versus repetitive transcranial magnetic stimulation for treatment-resistant depression: a randomized controlled trial
Disruption in reciprocal connectivity between the right anterior insula and the left dorsolateral prefrontal cortex is associated with depression and may be a target for neuromodulation. In a five-center, parallel, double-blind, randomized controlled trial we personalized resting-state functional magnetic resonance imaging neuronavigated connectivity-guided intermittent theta burst stimulation (cgiTBS) at a site based on effective connectivity from the right anterior insula to the left dorsolateral prefrontal cortex. We tested its efficacy in reducing the primary outcome depression symptoms measured by the GRID Hamilton Depression Rating Scale 17-item over 8, 16 and 26âweeks, compared with structural magnetic resonance imaging (MRI) neuronavigated repetitive transcranial magnetic stimulation (rTMS) delivered at the standard stimulation site (F3) in patients with âtreatment-resistant depressionâ. Participants were randomly assigned to 20âsessions over 4â6âweeks of either cgiTBS (nâ=â128) or rTMS (nâ=â127) with resting-state functional MRI at baseline and 16âweeks. Persistent decreases in depressive symptoms were seen over 26âweeks, with no differences between arms on the primary outcome GRID Hamilton Depression Rating Scale 17-item score (intention-to-treat adjusted mean, â0.31, 95% confidence interval (CI) â1.87, 1.24, Pâ=â0.689). Two serious adverse events were possibly related to TMS (mania and psychosis). MRI-neuronavigated cgiTBS and rTMS were equally effective in patients with treatment-resistant depression over 26âweeks (trial registration no. ISRCTN19674644)
Evaluating the Effects of Kidney Preservation at 10 °C with Hemopure and Sodium Thiosulfate in a Rat Model of Syngeneic Orthotopic Kidney Transplantation
Kidney transplantation is preferred for end-stage renal disease. The current gold standard for kidney preservation is static cold storage (SCS) at 4 °C. However, SCS contributes to renal graft damage through ischemiaâreperfusion injury (IRI). We previously reported renal graft protection after SCS with a hydrogen sulfide donor, sodium thiosulfate (STS), at 4 °C. Therefore, this study aims to investigate whether SCS at 10 °C with STS and Hemopure (blood substitute), will provide similar protection. Using in vitro model of IRI, we subjected rat renal proximal tubular epithelial cells to hypoxiaâreoxygenation for 24 h at 10 °C with or without STS and measured cell viability. In vivo, we preserved 36 donor kidneys of Lewis rats for 24 h in a preservation solution at 10 °C supplemented with STS, Hemopure, or both followed by transplantation. Tissue damage and recipient graft function parameters, including serum creatinine, blood urea nitrogen, urine osmolality, and glomerular filtration rate (GFR), were evaluated. STS-treated proximal tubular epithelial cells exhibited enhanced viability at 10 °C compared with untreated control cells (p p < 0.05) in the early time period after the transplant, but long-term function did not reach significance. Overall, renal graft preservation at 10 °C with STS and Hemopure supplementation has the potential to enhance graft function and reduce kidney damage, suggesting a novel approach to reducing IRI and post-transplant complications
LC/MS/MS Bioanalysis of ProteinâDrug ConjugatesîžThe Importance of Incorporating Succinimide Hydrolysis Products
Bioanalysis of antibodyâdrug
conjugates (ADCs) is challenging
due to the complex, heterogeneous nature of their structures and their
complicated catabolism. To fully describe the pharmacokinetics (PK)
of an ADC, several analytes are commonly quantified, including total
antibody, conjugate, and payload. Among them, conjugate is the most
challenging to measure, because it requires detection of both small
and large molecules as one entity. Existing approaches to quantify
the conjugated species of ADCs involve a ligand binding assay (LBA)
for conjugated antibody or hybrid LBA/liquid chromatography/tandem
mass spectrometry (LC/MS/MS) for quantitation of conjugated drug.
In our current work for a proteinâdrug conjugate (PDC) using
the Centyrin scaffold, a similar concept to ADCs but with smaller
protein size, an alternative method to quantify the conjugate by using
a surrogate peptide approach, was utilized. The His-tagged proteins
were isolated from biological samples using immobilized metal affinity
chromatography (IMAC), followed by trypsin digestion. The tryptic
peptide containing the linker attached to the payload was used as
a surrogate of the conjugate and monitored by LC/MS/MS analysis. During
method development and its application, we found that hydrolysis of
the succinimide ring of the linker was ubiquitous, taking place at
many stages during the lifetime of the PDC including in the initial
drug product, in vivo in circulation in the animals, and ex vivo during
the trypsin digestion step of the sample preparation. We have shown
that hydrolysis during trypsin digestion is concentration-independent
and consistent during the work flowîžtherefore, having no impact
on assay performance. However, for samples that have undergone extensive
hydrolysis prior to trypsin digestion, significant bias could be introduced
if only the non-hydrolyzed form is considered in the quantitation.
Therefore, it is important to incorporate succinimide hydrolysis products
in the quantitation method in order to provide an accurate estimation
of the total conjugate level. More importantly, the LC/MS/MS-based
method described here provides a useful tool to quantitatively evaluate
succinimide hydrolysis of ADCs in vivo, which has been previously
reported to have significant impact on their stability, exposure,
and efficacy
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A Randomized Study of Immune Plasma for the Treatment of Severe Influenza
Summary Background: Influenza causes significant morbidity and mortality despite currently available treatments. Anecdotal reports suggest plasma with high antibody titers towards influenza may be of benefit in the treatment of severe influenza. Methods: We conducted a randomized, open-label, multicenter phase 2 trial at 29 academic medical centers in the United States to assess the safety and efficacy of anti-influenza plasma with hemagglutination inhibition (HAI) antibody titers of â„ 1:80 to the infecting strain. Hospitalized children and adults (including pregnant women) with severe influenza A or B (defined as hypoxia or tachypnea) were randomly assigned to receive either 2 units (or pediatric equivalent) of anti-influenza plasma plus standard care (P+S), versus standard care alone (S), and were followed for 28 days. The primary endpoint was time to normalization of patientsâ respiratory status (respiratory rate of †20 for adults or age defined thresholds of 20â38 for children), and a room air saturation of oxygen â„ 93%. ClinicalTrials.gov Identifier: NCT01052480 Findings: Between January 13, 2011 and March 2, 2015, 113 participants were screened, and 98 were randomized. Of the participants with confirmed influenza, 28 of 42 (67%) of P+S participants normalized their respiratory status by Day 28, as compared to 24 of 45 (53%) of S participants (p=0·069). The estimated hazard ratio comparing P+S to S was 1·71 (95% CI: 0·96 to 3·06). Six participants died, 1 (2%) and 5 (10%) from the P+S and S arms respectively (p=0·093). P+S participants had non-significant reductions in days in hospital (median 6 vs. 11 days, p=0·13) and days on mechanical ventilation (median 0 vs. 3 days, p=0·14), and significantly improved clinical status at Day 7 (p=0·020). Fewer P+S participants experienced SAEs compared to S recipients (20% vs. 38%, p= 0·041), the most frequent of which were acute respiratory distress syndrome (1 [2%] vs 2 [4%]) and stroke (1 [2%] vs 2 [4%]). Interpretation Results from this Phase II randomized trial of immune plasma for the treatment of severe influenza provides support for a possible benefit of immunotherapy across the primary and secondary endpoints. A Phase III randomized trial is now underway to further evaluate this intervention