Citations

AbstractIntroductionA few copy number variations (CNVs) have been reported for Alzheimer's disease (AD). However, there is a lack of a systematic investigation of CNVs in AD based on whole genome sequencing (WGS) data.MethodsWe used four methods to identify consensus CNVs from the WGS data of 1,411 individuals and further investigated their functional roles in AD using the matched transcriptomic and clinicopathological data.ResultsWe identified 3,012 rare AD‐specific CNVs whose residing genes are enriched for cellular glucuronidation and neuron projection pathways. Genes whose mRNA expressions are significantly correlated with common CNVs are involved in major histocompatibility complex class II receptor activity. Integration of CNVs, gene expression, and clinical and pathological traits further pinpoints a key CNV that potentially regulates immune response in AD.DiscussionWe identify CNVs as potential genetic regulators of immune response in AD. The identified CNVs and their downstream gene networks reveal novel pathways and targets for AD.

R47H- TREM2 mutation enhances AKT signaling in human AD microglia and mediates proinflammatory and synaptic toxicity in a tauopathy mouse model.

AbstractLiposomal irinotecan is a liposomal formulation of irinotecan, which prolongs circulation of irinotecan and its active metabolite SN‐38. A population pharmacokinetic (PK) model was developed based on data from seven studies (N = 440). Adequacy of the model was assessed using multiple methods, including visual predictive check. Associations between PK exposure and the incidence of diarrhea (grade ≥3) and neutropenia adverse events (AEs) (grade ≥3) at first event in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC) were investigated using logistic regression based on data from two studies (the phase III NAPOLI‐1 [N = 260] and phase I/II NCT02551991 [N = 56] trials). The PKs of total irinotecan was described by a two‐compartment model with first‐order elimination, with SN‐38 formed directly by a first‐order constant from the central compartment of irinotecan or after using a transit compartment. Clearance was 17.9 L/week (0.107 L/h) and 19,800 L/week (118 L/h) for total irinotecan and SN‐38, respectively. The UGT1A1*28 7/7 homozygous genotype had no significant impact on SN‐38 clearance. Model evaluation was satisfactory for both irinotecan and SN‐38. The incidence of diarrhea (grade ≥3) at first event was significantly higher with increasing average concentrations of total irinotecan and SN‐38; there was no significant association between an increased risk of neutropenia AEs (grade ≥3) at first event and average SN‐38 concentrations. In summary, the PKs of total irinotecan and SN‐38 after administration of liposomal irinotecan were well‐described by the model. The UGT1A1*28 status had no significant impact on the PKs of liposomal irinotecan.

Abstract Not all apolipoprotein E ( APOE ) ε4 carriers who survive to advanced age develop Alzheimer's disease (AD); factors attenuating the risk of ε4 on AD may exist. Guided by the top ε4‐attenuating signals from methylome‐wide association analyses (N = 572, ε4+ and ε4–) of neurofibrillary tangles and neuritic plaques, we conducted a meta‐analysis for pathological AD within the ε4+ subgroups (N = 235) across four independent collections of brains. Cortical RNA‐seq and microglial morphology measurements were used in functional analyses. Three out of the four significant CpG dinucleotides were captured by one principal component (PC1), which interacts with ε4 on AD, and is associated with expression of innate immune genes and activated microglia. In ε4 carriers, reduction in each unit of PC1 attenuated the odds of AD by 58% (odds ratio = 2.39, 95% confidence interval = [1.64,3.46], P = 7.08 × 10 –6 ). An epigenomic factor associated with a reduced proportion of activated microglia (epigenomic factor of activated microglia, EFAM) appears to attenuate the risk of ε4 on AD.

Abstract Background Advanced age is a major risk factor for the development of many diseases including those affecting the central nervous system. Wild-type isocitrate dehydrogenase glioblastoma (IDHwt GBM) is the most common primary malignant brain cancer and accounts for ≥90% of all adult GBM diagnoses. Patients with IDHwt GBM have a median age of diagnosis at 68–70 years of age, and increasing age is associated with an increasingly worse prognosis for patients with this type of GBM. Methods The Surveillance, Epidemiology, and End Results, The Cancer Genome Atlas, and the Chinese Glioma Genome Atlas databases were analyzed for mortality indices. Meta-analysis of 80 clinical trials was evaluated for log hazard ratio for aging to tumor survivorship. Results Despite significant advances in the understanding of intratumoral genetic alterations, molecular characteristics of tumor microenvironments, and relationships between tumor molecular characteristics and the use of targeted therapeutics, life expectancy for older adults with GBM has yet to improve. Conclusions Based upon the results of our analysis, we propose that age-dependent factors that are yet to be fully elucidated, contribute to IDHwt GBM patient outcomes.

Increasing age is a major risk factor for calcific aortic valve disease (CAVD). Interestingly, SIRT6 knockout mice have a marked progeroid phenotype, and we recently reported that sirtuin enzyme expression is dramatically reduced with aging and that SIRT6 expression is reduced further in valves from patients with end-stage CAVD. It is unknown, however, whether experimentally reducing SIRT6 promotes osteogenic signaling in the valve and ultimately accelerates progression of CAVD. Thus, we used cultured mouse aortic valve interstitial cells and ldlr-deficient, apolipoprotein B100-only mice (LA) that were SIRT6 wild-type (LA-SIRT6 +/+ ) or heterozygous (LA-SIRT6 +/- ) and fed a Western diet for 3 or 12 months to determine the role of SIRT6 in valve calcification. In vitro , reduction of SIRT6 increased histone acetylation and significantly increased mRNA and protein levels of the osteogenic genes Runx2 and Sp7 in response to bone morphogenetic protein 2 (100ng/ml BMP2 for 18 hours), and siRNA knockdown of SIRT6 increased mRNA levels of Sp7 even in the absence of exogenous bone morphogens. Using high-resolution ultrasound to evaluate aortic valve function in vivo, we found that 3 month old LA-SIRT6 +/- mice did not have significant impairments in valve function compared to LA-SIRT6 +/+ mice. In contrast, 12 month old LA-SIRT6 +/- had dramatically worsened aortic valve dysfunction and stenosis compared to LA-SIRT6 +/+ mice, which was also associated with reductions in left ventricular ejection fraction. Collectively, our data strongly suggest SIRT6 plays a critical role in the tonic repression of osteogenic signaling in the aortic valve, and that age-related reductions in SIRT6 are likely to increase susceptibility to valve calcification in response to risk factors for CAVD such as hypercholesterolemia. Collectively, increasing activity of SIRT6 or reducing acetylation of its targets may serve as viable therapeutic strategies to slow progression of age-related valvular calcification and stenosis.

Endothelial cell senescence promotes inflammation and impairs endothelium-dependent vasodilation. While aging, hypercholesterolemia, and caloric excess are known to drive cellular senescence in part through activation of mTOR, it is unknown whether reducing mTOR signaling can improve vasomotor function in aging mice. Here, we used hypercholesterolemic mice (Ldlr -/- /apoB 100/100 , or LA) carrying intact copies of mTOR (LA-mTOR +/+ ) or were deficient in one copy of mTOR (LA- mTOR +/- ). Mice were fed Western Diet for 6 or 12 months, and vasomotor function in aorta was evaluated using isolated organ chamber baths. Maximum relaxation to acetylcholine (MR ACH ) was progressively impaired from 6 months to 12 months in LA-mTOR +/+ mice (55±4% and 30±4%, respectively). In contrast to our hypothesis, however, MR ACH was not significantly improved in LA-mTOR +/- mice at either time point (62±3% and 35±5%, respectively). Interestingly, a subgroup analysis showed significant improvement in MR ACH in male mice at the 6-month point (male LA-mTOR +/+ mice = 30 ± 9% vs male LA-mTOR +/- mice = 55±4%; p < 0.01), whereas vasomotor function in female mice was nearly identical across groups. There was no significant difference at the 12-month point (male LA-mTOR +/+ mice = 19 ± 3% vs male LA-mTOR +/- mice = 22 ± 5%). Relaxation to acetylcholine was attenuated by L-NAME at 6 months and 12 months (but identical between genotypes) and relaxation to nitroprusside was identical between strains at each time point, suggesting that changes in endothelial function were not masked by compensatory mechanisms (e.g., endothelium-derived hyperpolarizing factors). Furthermore, reduction of mTOR did not elicit changes in maximal tension generated in response to Prostaglandin F 2 α at either time point. Collectively, despite compelling evidence from in vitro model systems, genetic reduction of mTOR signaling in vivo does not appear to be sufficient to improve vasomotor function in our model of aging hypercholesterolemic mice. Our data do, however, shed light on a potential role of sex in dictating phenotypic changes in early to moderate stages of disease, which warrants further investigation.

Marfan syndrome (MFS) is a genetic disease with a mutation for the microfibrillar constituent protein fibrillin-1 being the most prevalent. MFS is often associated with progressive aortic root dilation, ultimately progressing to aortic aneurysm and dissection. While recent work has shown that increased angiotensin-II receptor type-1 and transforming growth factor beta (TGF-β) signaling contributes to aneurysm formation in aorta, efficacious therapeutic targets remain elusive. Given previous reports of progeriod phenotypes in a subset of Marfan patients, we sought to determine whether there are molecular changes that are consistent with accelerated aging in a mouse model of Marfan syndrome. In mice carrying a loss-of-function mutation in fibrillin-1, we assessed aortic root dimensions by echocardiography and gene expression levels of TGF-β1-3, runt related transcription factor 2 (RUNX2), and the cellular senescent marker CDKN2A by quantitative real time PCR at 3 and 14 months of age. As expected, aortic sinus dimensions did not change significantly with aging in wild type mice, but increased dramatically in fibrillin-1 mutant mice compared to wild-type littermate controls and with age (p < 0.05 for both). TGF-β1 ligand expression paralleled age and disease-dependent changes in aortic dimensions, however TGF-β2 and TGF-β3 mRNA levels did not. Aortic dilatation was associated with increased gene expression of RUNX2 with aging and in marfanoid mice. Interestingly, fibrillin-1 mutant mice demonstrated marked increases in expression of the anti-proliferative cell-cycle checkpoint protein CDKN2A at both time points, and correlated with changes in TGF-β1 (R 2 =0.54) and RUNX2 (R 2 =0.69) mRNA. CDNK2A gene expression patterns, however, demonstrated a poor correlation with expression of TGF-β2 and TGF-β3 (R 2 =0.04 and 0.06. respectively). Collectively, these data lend insight into novel mechanisms that may regulate development of aortic root dilation in patients MFS and are the first to implicate increased senescent cell burden in Marfan syndrome. Furthermore, we propose that clearance of senescent cells could be a viable therapeutic intervention to slow progression aortic root-dilation and aneurysm in patients with Marfan syndrome.

Increasing age is the greatest risk factor for development and progression of calcific aortic valve disease (CAVD), and mitochondrial dysfunction has been implicated in the pathogenesis of cardiovascular calcification. Previous findings by our group suggested a significant reduction in expression of multiple sirtuin (SIRT) isoforms in normocholesterolemic aged mouse aortic valves, however, it is unclear if losses in SIRT3—a major mitochondrial SIRT isoform—modulates progression of aortic valve calcification. Therefore, we hypothesized that loss of SIRT3 in a hypercholesterolemic mouse model of CAVD will result in augmented calcium burden in aortic valve, increased osteogenic signaling, and impaired aortic valve function. To test this we used mice that were Ldlr -/- /ApoB 100/100 mice that were either wild-type (LA-SIRT3 +/+ ) or null for SIRT3 (LA-SIRT3 -/- ) and fed a western diet (TD88137) for 12 months. Alizarin red was used to quantitate calcium burden, qRT-PCR was used to measure changes in mRNA levels, and high-resolution echocardiography was used to assess aortic valve function (cusp separation distance). In line with our hypothesis, we observed a substantial increase in calcium burden in LA-SIRT3 -/- mice compared to their LA-SIRT3 +/+ littermates(11.7±4.0, 4.8±1.8; respectively). Interestingly, expression of Runx2 and osterix—classic markers of osteogenic differentiation—were decreased in LA-SIRT3 -/- mice compared to their LA-SIRT3 +/+ littermates. Expression of Msx2, were markedly increased in aortic valve tissue from LA-SIRT3-deficient mice. Despite these histological and molecular changes, SIRT3 deletion did not alter cusp separation distance (LA-SIRT3 +/+ = 0.81±0.04; LA-SIRT3 -/- = 0.81±0.02). Collectively, this data suggest losses in SIRT3 can contribute to accelerated valve calcification through unclear molecular mechanisms, but these changes are not sufficient to drive reductions in cusp separation distance. Additional experiments delineating the histopathological and molecular sequelae of SIRT3 deletion will be critical to understanding its role in the pathogenesis of CAVD.

Marfan syndrome is a connective tissue disorder frequently driven by mutations in the fibrillin-1 gene (Fbn1). This results in multiple aberrant cardiovascular phenotypes, including aortic aneurysm and mitral valve prolapse. While the molecular changes underlying aortic aneurysm formation have been extensively studied, the molecular underpinnings of mitral valve prolapse in this syndrome remain poorly understood. Therefore, we hypothesized that smad2/3 phosphorylation would be significantly increased in both aorta and mitral valve from Fbn1 +/1037G mice with Marfan syndrome and associated with impaired anti-inflammatory signaling in both tissues. We used young (3 months) mice that were wild-type (Fbn1 +/+ ) or fibrillin-1 mutant (Fbn1 +/1037G ) and fed a normal chow diet. qRT-PCR was used to measure mRNA levels in aortic arch and mitral valve tissue, and fluorescent immunohistochemistry to evaluate changes in canonical TGFβ signaling. Consistent with previous reports, TGF-β1 mRNA levels were increased in Fbn1 +/1037G compared to wild-type mice in both aorta and mitral valve. Interestingly, while p-SMAD2/3 protein levels were increased in aorta from Fbn1 +/1037G mice, we were surprised to find that p-SMAD2/3 protein levels were decreased in mitral valve from Fbn1 +/1037G mice compared their wild-type littermates. Given the emerging role of inflammatory signaling in accelerated development of Marfan phenotypes, we sought to determine whether there were compensatory or maladaptive changes in IL10 (a known inhibitor of p-SMAD2/3). In aorta, IL10 mRNA levels were decreased in Fbn1 +/1037G compared to Fbn1 +/+ mice, suggesting a maladaptive response. In contrast, IL10 levels in mitral valve tissue were significantly increased in Fbn1 +/1037G mice compared to their wild-type littermates, suggesting a compensatory/protective response. Collectively, these data suggest that tissue-specific changes in IL10 levels may modulate p-SMAD2/3 signaling in aorta and mitral valve, which may be a key permissive step in the onset of Marfan-related phenotypes. Future work to experimentally determine the role of IL10 in the regulation of canonical and non-canonical TGFβ signaling and the penetrance of Marfan-associated phenotypes is warranted.