Evaluating the link between immune characteristics and attention deficit hyperactivity disorder through a bi-directional Mendelian randomization study.

Context: Despite the recognition of attention deficit hyperactivity disorder (ADHD) as a multifaceted neurodevelopmental disorder, its core causes are still ambiguous. The objective of this study was to explore if the traits of circulating immune cells contribute causally to susceptibility to ADHD. Methods: By employing a unified GWAS summary data covering 731 immune traits from the GWAS Catalog (accession numbers from GCST0001391 to GCST0002121), our analysis focused on the flow cytometry of lymphocyte clusters, encompassing 3,757 Sardinians, to identify genetically expected immune cells. Furthermore, we obtained summarized GWAS statistics from the Psychiatric Genomics Consortium to evaluate the genetic forecasting of ADHD. The studies employed ADHD2019 (20,183 cases and 35,191 controls from the 2019 GWAS ADHD dataset) and ADHD2022 (38,691 cases and 275,986 controls from the 2022 GWAS ADHD dataset). Through the examination of genome-wide association signals, we identified shared genetic variances between circulating immune cells and ADHD, employing the comprehensive ADHD2022 dataset. We primarily utilized inverse variance weighted (IVW) and weighted median methods in our Mendelian randomization research and sensitivity assessments to evaluate diversity and pleiotropy. Results: After adjusting for false discovery rate (FDR), three distinct immunophenotypes were identified as associated with the risk of ADHD: CD33 in Im MDSC (OR=1.03, CI: 1.01~1.04, P=3.04×10-5, PFDR =0.015), CD8br NKT %T cell (OR=1.08, 95%CI: 1.04~1.12, P=9.33×10-5, PFDR =0.023), and CD8br NKT %lymphocyte (OR=1.08, 95%CI: 1.03~1.12, P=3.59×10-4, PFDR =0.066). Furthermore, ADHD showed no statistical effects on immunophenotypes. It's worth noting that 20 phenotypes exist where ADHD's appearance could diminish 85% of immune cells, including FSC-A in myeloid DC (ß= -0.278, 95% CI: 0.616~0.931, P=0.008), CD3 in CD45RA- CD4+ (ß= -0.233, 95% CI: 0.654~0.960, P=0.017), CD62L- monocyte AC (ß=0.227, 95% CI: 0.038~1.518, P=0.019), CD33 in CD33br HLA DR+ CD14dim (ß= -0.331, 95% CI: 0.543~0.950, P=0.020), and CD25 in CD39+ resting Treg (ß=0.226, 95% CI: 1.522, P=0.022), and FSC-A in monocytes (ß= -0.255, 95% CI: 0.621~0.967, P=0.234), among others. Conclusion: Studies indicate that the immune system's response influences the emergence of ADHD. The findings greatly improve our understanding of the interplay between immune responses and ADHD risk, aiding in the development of treatment strategies from an immunological perspective.

A bidirectional Mendelian randomization study about the role of morning plasma cortisol in attention deficit hyperactivity disorder.

Context: Cortisol, a hormone regulated by the hypothalamic-pituitary-adrenal (HPA) axis, has been linked to attention deficit hyperactivity disorder (ADHD). The nature of the relationship between cortisol and ADHD, and whether it is causal or explained by reverse causality, remains a matter of debate. Objective: This study aims to evaluate the bidirectional causal relationship between morning plasma cortisol levels and ADHD. Methods: This study used a bidirectional 2-sample Mendelian randomization (MR) design to analyze the association between morning plasma cortisol levels and ADHD using genetic information from the authoritative Psychiatric Genomics Collaboration (PGC) database (n = 55,347) and the ADHD Working Group of the CORtisol NETwork (CORNET) Consortium (n = 12,597). MR analyses were employed: inverse variance weighting (IVW), MR-Egger regression, and weighted medians. OR values and 95% CI were used to evaluate whether there was a causal association between morning plasma cortisol levels on ADHD and ADHD on morning plasma cortisol levels. The Egger-intercept method was employed to test for level pleiotropy. Sensitivity analysis was performed using the "leave-one-out" method, MR pleiotropy residual sum, and MR pleiotropy residual sum and outlier (MR-PRESSO). Results: Findings from bidirectional MR demonstrated that lower morning plasma cortisol levels were associated with ADHD (ADHD-cortisol OR = 0.857; 95% CI, 0.755-0.974; P = 0.018), suggesting there is a reverse causal relationship between cortisol and ADHD. However, morning plasma cortisol levels were not found to have a causal effect on the risk of ADHD (OR = 1.006; 95% CI, 0.909-1.113; P = 0.907), despite the lack of genetic evidence. The MR-Egger method revealed intercepts close to zero, indicating that the selected instrumental variables had no horizontal multiplicity. The "leave-one-out" sensitivity analysis revealed stable results, with no instrumental variables significantly affecting the results. Heterogeneity tests were insignificant, and MR-PRESSO did not detect any significant outliers. The selected single-nucleotide polymorphisms (SNPs) F were all >10, indicating no weak instrumental variables. Thus, the overall MR analysis results were reliable. Conclusion: The study findings suggest a reverse causal relationship between morning plasma cortisol levels and ADHD, with low cortisol levels associated with ADHD. No genetic evidence was found to support a causal relationship between morning plasma cortisol levels and the risk of ADHD. These results suggest that ADHD may lead to a significant reduction in morning plasma cortisol secretion.

[Role of nuclear factor-kappaB on emodin-induced sensitization of pancreatic cancer to gemcitabine].

In view of gemcitabine resistance has limited clinical activity of gemcitabine as a cellulotoxic drug in pancreatic cancer patients, this study is designed to investigate the effect of emodin on the sensitivity of pancreatic cancer to gemcitabine as well as its mechanism. After gemcitabine-resistant pancreatic cancer cell line (SW1990/GZ) was established by escalating doses of gemcitabine serially in pancreatic cancer cell line (SW1990). The cellular proliferation was detected by cell counting kit-8 (CCK-8) assay. Flow cytometry (FCM) was used to determine apoptosis of pancreatic cancer cells. The activity of NF-kappaB in pancreatic cancer cells was measured by electrophoretic mobility shift assay (EMSA). Western blotting was used to detect the protein expression of Bcl-2 and Survivin in SW1990/GZ cells. Metastatic model simulating human pancreatic cancer was established by orthotopic implantation of histologically intact human tumor tissue into pancreatic wall of nude mice. Also, immunohistochemistry was used to detect the positive expression of Ki-67, NF-kappaB, Bcl-2 and Survivin in the tumors. The results show that pretreatment of cells with emodin followed by gemcitabine induced a higher percentage of growth inhibition and apoptosis of pancreatic cancer cells than that of gemcitabine alone. In addition to in vitro results, emodin in combination with gemcitabine is much more effective as an antitumor agent compared to either agent alone in the orthotopic tumor model. Further study showed that the emodin with or without gemcitabine significantly down-regulates NF-kappaB and its regulated molecules such as Bcl-2 and Survivin proteins both in vitro and in vivo. It is concluded that inactivation of NF-kappaB signaling pathway by emodin resulting in the chemosensitization of pancreatic cancer to gemcitabine, which is likely to be an important and novel strategy for the treatment of pancreatic cancer.