Citations

Background. Lynch syndrome is the most common genetic predisposition for hereditary cancer. Carriers of pathogenic changes in mismatch repair (MMR) genes have an increased risk of developing colorectal (CRC), endometrial, ovarian, urinary tract, prostate, and other cancers, depending on which gene is malfunctioning. In Lynch syndrome, differences in cancer incidence (penetrance) according to the gene involved have led to the stratification of cancer surveillance. By contrast, any differences in penetrance determined by the type of pathogenic variant remain unknown. Objective. To determine cumulative incidences of cancer in carriers of truncating and missense or aberrant splicing pathogenic variants of the MLH1 and MSH2 genes. Methods. Carriers of pathogenic variants of MLH1 (path_MLH1) and MSH2 (path_MSH2) genes filed in the Prospective Lynch Syndrome Database (PLSD) were categorized as truncating or missense/aberrant splicing according to the InSiGHT criteria for pathogenicity. Results. Among 5199 carriers, 1045 had missense or aberrant splicing variants, and 3930 had truncating variants. Prospective observation years for the two groups were 8205 and 34,141 years, respectively, after which there were no significant differences in incidences for cancer overall or for colorectal cancer or endometrial cancers separately. Conclusion. Truncating and missense or aberrant splicing pathogenic variants were associated with similar average cumulative incidences of cancer in carriers of path MLH1 and path_MSH2.

Abstract Demonstrating that treatments are clinically meaningful across the Alzheimer's disease (AD) continuum is critical for meeting our goals of accelerating a cure by 2025. While this topic has been a focus of several Alzheimer's Association Research Roundtable (AARR) meetings, there remains no consensus as to what constitutes a “clinically meaningful outcome” in the eyes of patients, clinicians, care partners, policymakers, payers, and regulatory bodies. Furthermore, the field has not come to agreement as to what constitutes a clinically meaningful treatment effect at each stage of disease severity. The AARR meeting on November 19–20, 2019, reviewed current approaches to defining clinical meaningfulness from various perspectives including those of patients and care partners, clinicians, regulators, health economists, and public policymakers. Participants discussed approaches that may confer clinical relevance at each stage of the disease continuum and fostered discussion about what should guide us in the future.

Abstract Background: Many loci have been found to be associated with risk of epithelial ovarian cancer (EOC). However, although there is considerable variation in progression-free survival (PFS), no loci have been found to be associated with outcome at genome-wide levels of significance. Methods: We carried out a genome-wide association study (GWAS) of PFS in 2,352 women with EOC who had undergone cytoreductive surgery and standard carboplatin/paclitaxel chemotherapy. Results: We found seven SNPs at 12q24.33 associated with PFS (P < 5 × 10–8), the top SNP being rs10794418 (HR = 1.24; 95% CI, 1.15–1.34; P = 1.47 × 10–8). High expression of a nearby gene, ULK1, is associated with shorter PFS in EOC, and with poor prognosis in other cancers. SNP rs10794418 is also associated with expression of ULK1 in ovarian tumors, with the allele associated with shorter PFS being associated with higher expression, and chromatin interactions were detected between the ULK1 promoter and associated SNPs in serous and endometrioid EOC cell lines. ULK1 knockout ovarian cancer cell lines showed significantly increased sensitivity to carboplatin in vitro. Conclusions: The locus at 12q24.33 represents one of the first genome-wide significant loci for survival for any cancer. ULK1 is a plausible candidate for the target of this association. Impact: This finding provides insight into genetic markers associated with EOC outcome and potential treatment options. See related commentary by Peres and Monteiro, p. 1604

Abstract BackgroundCopy number variants (CNVs) are pervasive in the human genome but potential disease associations with rare CNVs have not been comprehensively assessed in large datasets. We analysed rare CNVs in genes and non-coding regions for 86,788 breast cancer cases and 76,122 controls of European ancestry with genome-wide array data.ResultsGene burden tests detected the strongest association for deletions in BRCA1 (P= 3.7E-18). Nine other genes were associated with a p-value < 0.01 including known susceptibility genes CHEK2 (P= 0.0008), ATM (P= 0.002) and BRCA2 (P= 0.008). Outside the known genes we detected associations with p-values < 0.001 for either overall or subtype-specific breast cancer at nine deletion regions and four duplication regions. Three of the deletion regions were in established common susceptibility loci.ConclusionsThis is the first genome-wide analysis of rare CNVs in a large breast cancer case-control dataset. We detected associations with exonic deletions in established breast cancer susceptibility genes. We also detected suggestive associations with non-coding CNVs in known and novel loci with large effects sizes. Larger sample sizes will be required to reach robust levels of statistical significance.

Background Prostaglandins, such as cyclooxygenase (COX), may play an important role in regulating the cerebral blood flow response to a stimulus. We have previously shown that the vasodilatory response to a chemical stimulus decreases with age, and this difference is abolished by COX inhibition. However, the effects of COX inhibition on the cerebrovascular response to an increase in metabolic demand during a cognitive challenge is unknown. This information is important due to the frequent use of COX inhibitors for pain management. Thus, the purpose of this study was to determine the effect of COX inhibition on the cerebrovascular response to a metabolic stimulus in young and older adults. Methods Seventy‐six participants, including 42 young adults (YA; 26 ± 5 y) and 34 older adults (OA; 64 ± 6 y) completed the Stroop Color Word Test, which is a test of executive function. A subset of 42 participants (n = 22 YA, n = 20 OA) also completed the N‐back Test, which is a test of working memory. Beat‐to‐beat middle cerebral artery velocity (MCAv) and mean arterial pressure (MAP) were measured at baseline and in response to each cognitive test. Cerebrovascular conductance index (CVCi) was calculated as MCAv/MAP. The response to each cognitive test was calculated as the peak percent change (%Δ) from baseline. Oral administration of the COX inhibitor Indomethacin (Indo) was given at 1.2mg/kg. Cognitive tests were then repeated after a 120‐minute wash‐in period. Results At baseline, YA had higher MCAv, CVCi, and lower MAP (p<0.01 for all) compared to OA. There were no significant differences between groups in the %Δ from baseline during the Stroop or N‐back test (p>0.05). During Indo, YA had higher MCAv (p<0.01), CVCi (p<0.01), and lower MAP (p<0.05) compared to OA. Indo decreased baseline MCAv and CVCi in both groups (p<0.01 for all) but had no effect on MAP (p>0.05). During Indo, the %Δ in MCAv during Stroop and N‐back was lower in YA (p<0.01) compared to baseline in YA. During Indo, the %Δ in MCAv was lower during Stroop in OA (p<0.01), with a trend for significance in OA during N‐back (p=0.06) compared to baseline. In YA during Indo, the %Δ in MAP was lower during Stroop (p<0.01) with a trend for significance during Nback (p=0.08) compared to baseline. In OA, the %Δ in MAP during N‐back was lower during Indo compared to baseline (p<0.05). Indo had no effect on the %Δ in CVCi (p>0.05). Importantly, there were group differences in the %Δ in MAP during Indo, such that the change was greater in OA compared with YA during Stroop (14.1 ± 1.3% vs. 10.6 ± 1.0%; p<0.05). Conclusion After administration of Indo, OA increased MAP to a greater extent during the Stroop test when compared to YA. These results suggest that OA required a larger increase in blood pressure to complete a test of executive function during COX inhibition. Because some COX inhibitors attenuate cerebral blood flow, OA may need to augment blood pressure to complete this metabolically‐challenging task. Support or Funding Information This research was funded by NIH grant HL118154. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

To understand the role of regulatory T cells in staphylococcal enterotoxin B‐induced toxic shock syndrome (TSS), we performed gene expression profiling in HLA‐DR3 transgenic mice using microarrays. We observed that at 3 hours after systemic exposure to SEB (10 μg), the splenic expression of FoxP3, a hall mark of regulatory T cells, was increased by 5 folds (p<0.005). In addition, other genes that regulate FoxP3 + Tregs were also significantly modulated by SEB. These include IL‐2R (27‐fold), IL‐2 (234‐fold), IL‐6 (689‐fold), IL‐21 (21‐fold), TGF‐B1 (0.7‐fold), IL‐17 (5.5‐fold) and IL‐22 (98‐fold). To further characterize the homeostasis of Tregs cells during superantigen‐induced TSS in vivo, HLA‐DR3 transgenic mice were first challenged with SEB and were administered BrdU in drinking water for 3 days. Mice were killed 3 days later and splenocytes analyzed by flow cytometry. We observed that in addition to FoxP3‐TCR Vβ8 + T cells, FoxP3 + TCR Vβ8 + T cells also significantly expanded in vivo as evident from their BrdU staining patterns. This indicated that SEB is able to activate Tregs as well. Depletion of Tregs using anti‐CD25 antibodies (clone PC‐61, 500 ug/mouse) 2 days prior to SEB challenge did not significantly alter serum cytokine levels as compared to control mice treated with rat IgG and SEB. Thus, T regulatory cells have a minimal role in SEB‐induced TSS.

Cux1 is a homeobox gene involved in cell cycle regulation and kidney development. Cux1 is upregulated in the kidneys of both mice and humans with autosomal dominant polycystic kidney disease (ADPKD). However, Cux1 transgenic mice do not develop cystic kidneys, indicating that upregulation of Cux1 alone is insufficient to develop PKD. Mice carrying a deletion of the C‐terminus of Cux1 (Cux1 tm2Ejn‐/‐ ) express a truncated protein that does not localize to the nucleus, resulting in functional loss of Cux1 transcriptional activity. To test the hypothesis that Cux1 is required to develop PKD, we generated collecting duct specific Pkd1 mutant mice (Pkd1 CD ) that were also homozygous for the Cux1 mutation. When kidneys isolated from newborn Pkd1 CD /Cux1 tm2Ejn ‐/‐ mice were examined, we found a marked reduction in cystic dilations compared to the kidneys isolated from newborn Pkd1 CD mice. We confirmed the Cre activity by crossing the Pkd1 CD and Pkd1 CD / Cux1 tm2Ejn ‐/‐ mice to the membrane‐targeted Tomato/Green Fluorescent Protein (mT/mG) double fluorescent reporter mouse strain (Gt(ROSA)26Sor tm4(ACTB‐tdTomato,‐EGFP)Luo /J), which carries a loxP‐flanked Tomato cassette. Immunofluorescence of kidney sections indicated that collecting duct derived cysts were positive for the excision event in the Pkd1 CD mice. In contrast, although collecting ducts were positive for the excision event in Pkd1 CD / Cux1 tm2Ejn ‐/‐ mice, none of the positive tubules were cystic. Taken together, our results suggest that Cux1 gene dosage influences the progression of cystic disease in an ADPKD mouse model.

By binding to a nebulin site on actin in skeletal myofibrils phalloidin (PH) causes a force decrease (phase 1) followed by an increase in force (phase 2). The initial force decrease likely reflects a disturbance in actin‐nebulin interaction. The aim of this work was to determine the role of myosin cross‐bridges (XBs) and Ca 2+ in PH‐induced force decrease in skinned rabbit psoas fibers. Force response to PH was studied in the presence of 30 mM 2,3‐Butanedione monoxime (an agent reducing a fraction of strongly bound XBs), where we found that the phase 2 response was suppressed and PH induced 60–70% force decrease. Pretreatment with PH of relaxed (pCa 9, strongly bound XBs are absent) or rigor (in the absence of ATP, all XBs are strongly bound to actin) muscles also resulted in force loss. At the same duration of pretreatment, the remaining force was higher and more sensitive to PH in the latter case. The same properties were found for dethiophalloidin (DTPH), where it was also shown that the force loss was essentially the same at pCa 4 and pCa 9. We concluded that rigor XBs, but not Ca 2+ , affect the rate of PH binding to actin in myofibrils. The XBs mediated changes in nebulin site on actin are supportive for suggested regulatory nebulin role. Supported by NIH grants HL68555 and HL37680.