HOPS-dependent lysosomal fusion controls Rab19 availability for ciliogenesis in polarized epithelial cells.

Primary cilia are sensory cellular organelles crucial for organ development and homeostasis. Ciliogenesis in polarized epithelial cells requires Rab19-mediated clearing of apical cortical actin to allow the cilium to grow from the apically docked basal body into the extracellular space. Loss of the lysosomal membrane-tethering homotypic fusion and protein sorting (HOPS) complex disrupts this actin clearing and ciliogenesis, but it remains unclear how the ciliary function of HOPS relates to its canonical function in regulating late endosome-lysosome fusion. Here, we show that disruption of HOPS-dependent lysosomal fusion indirectly impairs actin clearing and ciliogenesis by disrupting the targeting of Rab19 to the basal body, and that this effect is specific to polarized epithelial cells. We also find that Rab19 functions in endolysosomal cargo trafficking in addition to having its previously identified role in ciliogenesis. In summary, we show that inhibition of lysosomal fusion leads to the abnormal accumulation of Rab19 on late endosomes, thus depleting Rab19 from the basal body and thereby disrupting Rab19-mediated actin clearing and ciliogenesis in polarized epithelial cells.

Hsa_circ_0001535 inhibits the proliferation and migration of ovarian cancer by sponging miR-593-3p, upregulating PTEN expression

Background Hsa_circ_0001535 is involved in biological processes in various tumors. However, the biological effects and related mechanism of hsa_circ_0001535 in ovarian cancer (OC) is unclear. This work is aimed to probe the biological function and underlying mechanism of hsa_circ_0001535 in OC, especially sponged with mi-RNA, require further elucidation. Methods Hsa_circ_0001535 expression in OC tissues and cell lines were examined by qRT-PCR. Hsa_circ_0001535 overexpression model was constructed by lentivirus-mediated transfection in two OC cell lines, and the biological functions of hsa_circ_0001535 were evaluated by CCK-8, transwell assay and Western blot. Dual luciferase reporter gene assay was respectively used to explore the relationship between hsa_circ_0001535 and miR-593-3p, as well as miR-593-3p and PTEN. The expression of miR-593-3p and PTEN were detected by qRT-PCR in two OC cell lines and OC tissues. Results Hsa_circ_0001535 was down-regulated in OC tissues and cell lines. Hsa_circ_0001535 overexpression inhibited proliferation, migration and EMT marker expression in OC cells. Of interest, hsa_circ_0001535 targeted miR-593-3p and reduced its RNA level in OC cells. PTEN was a target gene of miR-593-3p, which was up-regulated by inhibiting miR-593-3p in OC cells. Furthermore, miR-593-3p mimic treatment reversed the up-regulation of PTEN by hsa_circ_0001535 overexpression in OC cells. Conclusions The above results showed that hsa_circ_0001535 acted as a molecular sponge for miR-593-3p to repress miR-593-3p expression, and promoted the expression of PTEN, thus inhibited proliferation and migration of OC cells. Our research provides a potential therapeutic target for ovarian cancer patients (AU)

The involvement of PDIA2 gene in the progression of renal cell carcinoma is potentially through regulation of JNK signaling pathway

Renal cell carcinoma (RCC) with poor prognosis and high incidence rate is a common malignant disease. Current therapies could bring little benefit for the patients with advanced-stage RCC. PDIA2 is an isomerase responsible for protein folding and its role in cancer including RCC is under investigation. In this study, we found that PDIA2 was expressed much higher in RCC tissues than the control but the methylation level of PDIA2 promoter was lower based on the TCGA data. Patients with higher PDIA2 expression exerted worse survival. In clinical specimen, PDIA2 expression was correlated to patients’ clinical factors such as TNM stage (I/II vs III/IV, p = 0.025) and tumor size (≤ 7 cm vs > 7 cm, p = 0.004). Moreover, K-M analysis showed that PDIA2 was associated with patients’ survival in RCC. PDIA2 was expressed much higher in cancer cells A498 than 786-O than that in 293 T cells. After PDIA2 was knocked down, cell proliferation, migration and invasion was potently inhibited. But cell apoptotic rate increased reversely. Furthermore, the efficacy of Sunitinib on RCC cells was strengthened after PDIA2 knockdown. In addition, knockdown of PDIA2 gene leaded to downregulation of levels of JNK1/2, phosphorylated JNK1/2, c-JUN, and Stat3. But this inhibition was partially released when JNK1/2 was overexpressed. In consistent, cell proliferation was also partially recovered. In summary, PDIA2 plays important role in progression of RCC and JNK signaling pathway might be regulated by PDIA2. This study suggests PDIA2 as a candidate target for therapy of RCC (AU)

miR-17-5p slows progression of hepatocellular carcinoma by downregulating TGFBR2

Objective Downregulation of miR-17-5p has been reported in several cancers, but whether and how miR-17-5p is downregulated in hepatocellular carcinoma (HCC) is unknown. Here, we examined whether miR-17-5p is downregulated in HCC and whether that affects expression of its target gene encoding transforming growth factor β receptor 2 (TGFβR). Methods We screened for potential microRNAs (miRNAs) involved in HCC by analyzing published transcriptomes from HCC patients. Expression of miR-17-5p was measured in HCC cell lines and in tissues from HCC patients using quantitative real-time PCR. The in vitro effects of miR-17-5p on HCC cells were assessed by EdU proliferation assay, CCK-8 cell proliferation assay, colony-formation assay, transwell migration/invasion assay, wound healing assay, and flow cytometry. Effects of miR-17-5p were evaluated in vivo using mice with subcutaneous tumors. Effects of the miRNA on the epithelial–mesenchymal transition (EMT) were assessed, while its effects on TGFβR2 expression were analyzed using bioinformatics and a dual luciferase reporter assay. Results Patients with low miR-17-5p expression showed lower rates of overall and recurrence-free survival than patients with high miR-17-5p expression, and multivariate Cox regression identified low miR-17-5p expression as an independent predictor of poor overall survival in HCC patients. In vitro, miR-17-5p significantly inhibited HCC cell proliferation, migration, invasion, and the EMT, while promoting apoptosis. In vivo, it slowed the development of tumors. These protective effects of miR-17-5p were associated with downregulation of TGFβR2. Conclusion The miRNA miR-17-5p can negatively regulate the expression of TGFβR2 and inhibit the EMT, thereby slowing tumor growth in HCC, suggesting a potential therapeutic approach against HCC (AU)

Oncogenic roles of GPR176 in breast cancer: a potential marker of aggressiveness and a potential target of gene therapy

Background Belonging to the G-protein coupled receptor 1 family, G protein-coupled receptor 176 (GPR176) is associated with the Gz/Gx G-protein subclass and is capable of decreasing cAMP production. Methods GPR176 expression was detected by qRT-PCR, bioinformatics analysis, Western blot and immunohistochemistry, and compared with clinicopathological characteristics of breast cancer. GPR176-related genes and pathways were subjected to bioinformatic analysis. We also explored the effects of GPR176 on the phenotypes of breast cancer cells. Results Lower expression of GPR176 mRNA was seen in breast cancer than in normal tissues, but the opposite pattern was found for its protein (p < 0.05). GPR176 mRNA was associated with female sex, low T staging, non-Her-2+ subtypes, non-mutant p53 status in breast cancer (p < 0.05). GPR176 methylation was negatively correlated with its mRNA level and T staging in breast cancer, and was higher in breast cancer than normal tissues (p < 0.05). GPR176 protein expression was positively correlated with older age, small tumor size, and non-luminal-B subtype of breast cancers (p < 0.05). The differential genes of GPR176 were involved in receptor-ligand interaction, RNA maturation, and so forth (p < 0.05). GPR176-related genes were categorized into cell mobility, membrane structure, and so on (p < 0.05). GPR176 knockdown weakened the proliferation, glucose catabolism, anti-apoptosis, anti-pyroptosis, migration, invasion, and epithelial-mesenchymal transition of breast cancer cells. Conclusion These results indicate that GPR176 might be involved in the tumorigenesis and subsequent progression of breast cancer by deteriorating aggressive phenotypes. It might be utilized as a potential biomarker to indicate the aggressive behaviors and poor prognosis of breast cancer and a potential target of genetic therapy (AU)

Response of cells and tissues to shear stress.

Shear stress is essential for normal physiology and malignancy. Common physiological processes - such as blood flow, particle flow in the gut, or contact between migratory cell clusters and their substrate - produce shear stress that can have an impact on the behavior of different tissues. In addition, shear stress has roles in processes of biomedical interest, such as wound healing, cancer and fibrosis induced by soft implants. Thus, understanding how cells react and adapt to shear stress is important. In this Review, we discuss in vivo and in vitro data obtained from vascular and epithelial models; highlight the insights these have afforded regarding the general mechanisms through which cells sense, transduce and respond to shear stress at the cellular levels; and outline how the changes cells experience in response to shear stress impact tissue organization. Finally, we discuss the role of shear stress in collective cell migration, which is only starting to be appreciated. We review our current understanding of the effects of shear stress in the context of embryo development, cancer and fibrosis, and invite the scientific community to further investigate the role of shear stress in these scenarios.

ERK1/2-Dependent Phosphorylation of GABAB1(S867/T872), Controlled by CaMKIIß, Is Required for GABAB Receptor Degradation under Physiological and Pathological Conditions.

GABAB receptor-mediated inhibition is indispensable for maintaining a healthy neuronal excitation/inhibition balance. Many neurological diseases are associated with a disturbed excitation/inhibition balance and downregulation of GABAB receptors due to enhanced sorting of the receptors to lysosomal degradation. A key event triggering the downregulation of the receptors is the phosphorylation of S867 in the GABAB1 subunit mediated by CaMKIIß. Interestingly, close to S867 in GABAB1 exists another phosphorylation site, T872. Therefore, the question arose as to whether phosphorylation of T872 is involved in downregulating the receptors and whether phosphorylation of this site is also mediated by CaMKIIß or by another protein kinase. Here, we show that mutational inactivation of T872 in GABAB1 prevented the degradation of the receptors in cultured neurons. We found that, in addition to CaMKIIß, also ERK1/2 is involved in the degradation pathway of GABAB receptors under physiological and ischemic conditions. In contrast to our previous view, CaMKIIß does not appear to directly phosphorylate S867. Instead, the data support a mechanism in which CaMKIIß activates ERK1/2, which then phosphorylates S867 and T872 in GABAB1. Blocking ERK activity after subjecting neurons to ischemic stress completely restored downregulated GABAB receptor expression to normal levels. Thus, preventing ERK1/2-mediated phosphorylation of S867/T872 in GABAB1 is an opportunity to inhibit the pathological downregulation of the receptors after ischemic stress and is expected to restore a healthy neuronal excitation/inhibition balance.

Essential Oil of Bursera morelensis Promotes Cell Migration on Fibroblasts: In Vitro Assays.

Essential oils (EOs) are complex mixtures of volatile natural compounds. We have extensively studied the EO of Bursera morelensis, which demonstrates antibacterial, antifungal, anti-inflammatory, and wound-healing activities. The objective of this work was to determine the effect of this EO on fibroblast migration in a three-dimensional in vitro model. For the three-dimensional in vitro model, a series of fibrin hydrogel scaffolds (FSs) were built in which fibroblasts were cultured and subsequently stimulated with fibroblast growth factor (FGF) or EO. The results demonstrated that these FSs are appropriate for fibroblast culture, since no decrease in cell viability or changes in cell proliferation were found. The results also showed that this EO promotes cell migration four hours after stimulation, and the formation of cell projections (filopodia) outside the SF was observed. From these results, we confirmed that part of the mechanism of action of the essential oil of B. morelensis during the healing process is the stimulation of fibroblast migration to the wound site.

To stay in shape and keep moving: MLL emerges as a new transcriptional regulator of Rho GTPases.

RhoA, Rac1 and CDC42 are small G proteins that play a crucial role in regulating various cellular processes, such as the formation of actin cytoskeleton, cell shape and cell migration. Our recent results suggest that MLL is responsible for maintaining the balance of these small Rho GTPases. MLL depletion affects the stability of Rho GTPases, leading to a decrease in their protein levels and loss of activity. These changes manifest in the form of abnormal cell shape and disrupted actin cytoskeleton, resulting in reduced cell spreading and migration. Interestingly, their chaperone protein RhoGDI1 but not the Rho GTPases, is under the direct transcriptional regulation of MLL. Here, we comment on the possible implications of these observations on the signalling by Rho GTPases protein network.

Extracellular Vesicle MicroRNAs in Heart Failure: Pathophysiological Mediators and Therapeutic Targets.

Extracellular vesicles (EVs) are emerging mediators of intracellular and inter-organ communications in cardiovascular diseases (CVDs), especially in the pathogenesis of heart failure through the transference of EV-containing bioactive substances. microRNAs (miRNAs) are contained in EV cargo and are involved in the progression of heart failure. Over the past several years, a growing body of evidence has suggested that the biogenesis of miRNAs and EVs is tightly regulated, and the sorting of miRNAs into EVs is highly selective and tightly controlled. Extracellular miRNAs, particularly circulating EV-miRNAs, have shown promising potential as prognostic and diagnostic biomarkers for heart failure and as therapeutic targets. In this review, we summarize the latest progress concerning the role of EV-miRNAs in HF and their application in a therapeutic strategy development for heart failure.

Challenges and Opportunities for Equity in US School Meal Programs: A Scoping Review of Qualitative Literature Regarding the COVID-19 Emergency.

The emergency school meals program provided free meals to children in the United States (US) during COVID-19-related school closures. This scoping review aims to synthesize the existing qualitative empirical evidence published between March 2020 and January 2023 on the operations and utilization of emergency school meal programs during the pandemic. Qualitative, US-based peer-reviewed literature was collected from three sources: (1) parent review of all federal nutrition assistance programs; (2) systematic search of four databases; and (3) manual search of grey literature. Identified scientific articles and grey literature reports (n = 183) were uploaded into Covidence and screened for duplicates and inclusion/exclusion criteria. Our final sample included 21 articles/reports, including 14 mixed methods and seven qualitative-only projects. Articles spanned all U.S. states. Articles had similar research questions to understand school meals and/or general food access during COVID-19, with an emphasis on long-term policy implications. Hybrid deductive/inductive analytic coding was used to analyze data, utilizing domains from the Getting to Equity Framework (GTE). GTE considers multi-level factors that influence nutrition behavior while centering more equitable pathways to improve nutrition security and reduce adverse health. Findings were sorted into two categories: operational challenges during the pandemic and solutions to address inequities in school meal distribution during and after the pandemic, particularly during school closures such as summers or future emergencies. Key challenges related to supply chain issues, safety, and balancing families' needs with limited staff capacity. Programs addressed equity by (a) reducing deterrents through federally issued waivers and increased communications which allowed the serving of meals by programs to families who previously did not have access, (b) building community capacity through collaborations and partnerships which allowed for increased distribution, and (c) preparing and distributing healthy options unless barriers in supply chain superseded the effort. This review highlights the importance of emergency school meal programs and provides insights into addressing challenges and promoting equity in future out-of-school times. These insights could be applied to policy and practice change to optimize program budgets, increase reach equitably, and improve access to nutritious meals among populations at highest risk for nutrition insecurity.

Proteomic and functional characterisation of extracellular vesicles from collagen VI deficient human fibroblasts reveals a role in cell motility.

Extracellular vesicles (EVs) are key mediators of cell-to-cell communication. Their content reflects the state of diseased cells representing a window into disease progression. Collagen-VI Related Muscular Dystrophy (COL6-RD) is a multi-systemic disease involving different cell types. The role of EVs in this disease has not been explored. We compared by quantitative proteomics the protein cargo of EVs released from fibroblasts from patients with COL6-RD and controls. Isolated EVs contained a significant proportion of the most frequently reported proteins in EVs according to Exocarta and Vesiclepedia. We identified 67 differentially abundant proteins associated with vesicle transport and exocytosis, actin remodelling and the cytoskeleton, hemostasis and oxidative stress. Treatment of control fibroblasts with EVs from either patient or healthy fibroblasts altered significantly the motility of cells on a cell migration assay highlighting the functional relevance of EVs. In parallel, we analysed the secretome from the same cells and found a distinctly different set of 48 differentially abundant proteins related to extracellular matrix organisation and remodelling, growth factor response, RNA metabolism and the proteasome. The EVs and secretome sets of proteins only shared two identifiers indicating that the sorting of proteins towards EVs or the secretory pathway is tightly regulated for different functions.

CCR7 acts as both a sensor and a sink for CCL19 to coordinate collective leukocyte migration.

Immune responses rely on the rapid and coordinated migration of leukocytes. Whereas it is well established that single-cell migration is often guided by gradients of chemokines and other chemoattractants, it remains poorly understood how these gradients are generated, maintained, and modulated. By combining experimental data with theory on leukocyte chemotaxis guided by the G protein-coupled receptor (GPCR) CCR7, we demonstrate that in addition to its role as the sensory receptor that steers migration, CCR7 also acts as a generator and a modulator of chemotactic gradients. Upon exposure to the CCR7 ligand CCL19, dendritic cells (DCs) effectively internalize the receptor and ligand as part of the canonical GPCR desensitization response. We show that CCR7 internalization also acts as an effective sink for the chemoattractant, dynamically shaping the spatiotemporal distribution of the chemokine. This mechanism drives complex collective migration patterns, enabling DCs to create or sharpen chemotactic gradients. We further show that these self-generated gradients can sustain the long-range guidance of DCs, adapt collective migration patterns to the size and geometry of the environment, and provide a guidance cue for other comigrating cells. Such a dual role of CCR7 as a GPCR that both senses and consumes its ligand can thus provide a novel mode of cellular self-organization.

Chitosan oligosaccharide suppresses osteosarcoma malignancy by inhibiting CEMIP via the PI3K/AKT/mTOR pathway.

Osteosarcoma is a malignant bone tumor that is prone to metastasize early and primarily affects children and adolescents. Cell migration-inducing protein (CEMIP) plays a crucial role in the progression and malignancy of various tumor diseases, including osteosarcoma. Chitosan oligosaccharide (COS), an oligomer isolated from chitin, has been found to have significant anti-tumor activity in various cancers. This study investigates the effects of COS on CEMIP expression in osteosarcoma and explores the underlying mechanism. In present study, in vitro experiments were conducted to confirm the inhibitory activity of COS on human osteosarcoma cells. Our results demonstrate that COS possesses inhibitory effects against human osteosarcoma cells and significantly suppresses CEMIP expression in vitro. Next, we studied the inhibition of the expression of CEMIP by COS and then performed bioinformatics analysis to explore the potential inhibitory mechanism of COS against signaling pathways involved in regulating CEMIP expression. Bioinformatics analysis predicted a close association between the PI3K signaling pathway and CEMIP expression and that the inhibitory effect of COS on CEMIP expression may be related to PI3K signaling pathway regulation. The results of this study show that COS treatment significantly inhibits CEMIP expression and the PI3K/AKT/mTOR signaling pathway, as observed both in vitro and in vivo. This study demonstrates that COS could inhibit the expression of CEMIP, which is closely related to osteosarcoma malignancy. This inhibitory effect may be attributed to the inhibition of the PI3K/AKT/mTOR signaling pathway in vitro and in vivo.

Colonoscopy compliance and diagnostic yield in a large population-based colorectal cancer screening programme.

OBJECTIVES: With the intention of providing a reference for secondary prevention, our study provides some insight on diagnostic yield of factors influencing compliance with colonoscopy and the presence of advanced adenomas (AA). METHODS: We conducted large-scale CRC screening among local Tianjin residents aged 40-75 years between 2012 and 2019. A high-risk factor questionnaire (HRFQ) was distributed to each participant, followed by the performance of a fecal immunochemical test (FIT). Participants who tested positively for any of these items were advised to undergo a colonoscopy. Relevant basic information was collected from participants during CRC screening, and the screening data were sorted and analysed. RESULTS: A total of 5,670,924 people participated in CRC screening by the end of 2019, including 275,708 people in the high-risk group, and 74,685 (27.1%) people who underwent colonoscopy. The results of the logistic regression model demonstrated that participants with a history of mucous bloody stool (OR = 8.20, 95% CI: 7.92, 8.50, p < 0.001), chronic diarrhea (OR = 5.73, 95% CI: 5.57, 5.89, p < 0.001), and higher level of education (OR = 1.87, 95% CI: 1.80, 1.93, p < 0.001) were more likely to comply with a colonoscopy. Several factors including age (70-75 years old:OR = 3.72, 95% CI: 2.71, 5.10, p < 0.001), and FIT( +) (OR = 1.65, 95% CI: 1.42,1.90, p < 0.001) were identified to be associated with the presence of AA. CONCLUSIONS: Increased compliance with colonoscopy is urgently needed. Our findings can inform the design of future effective large-scale population-based CRC screening programmes.

Topological data analysis of spatial patterning in heterogeneous cell populations: clustering and sorting with varying cell-cell adhesion.

Different cell types aggregate and sort into hierarchical architectures during the formation of animal tissues. The resulting spatial organization depends (in part) on the strength of adhesion of one cell type to itself relative to other cell types. However, automated and unsupervised classification of these multicellular spatial patterns remains challenging, particularly given their structural diversity and biological variability. Recent developments based on topological data analysis are intriguing to reveal similarities in tissue architecture, but these methods remain computationally expensive. In this article, we show that multicellular patterns organized from two interacting cell types can be efficiently represented through persistence images. Our optimized combination of dimensionality reduction via autoencoders, combined with hierarchical clustering, achieved high classification accuracy for simulations with constant cell numbers. We further demonstrate that persistence images can be normalized to improve classification for simulations with varying cell numbers due to proliferation. Finally, we systematically consider the importance of incorporating different topological features as well as information about each cell type to improve classification accuracy. We envision that topological machine learning based on persistence images will enable versatile and robust classification of complex tissue architectures that occur in development and disease.

Design, synthesis, and biological evaluation of novel bivalent PI3K inhibitors for the potential treatment of cancer.

Phosphatidylinositol 3-kinase (PI3K) signaling is among the most common alterations in cancer and has become a key target for cancer drug development. Based on a 4-methyl quinazoline scaffold, we designed and synthesized a novel series of bivalent PI3K inhibitors with different linker lengths and types. Bivalent PI3K inhibitor 27 demonstrates improved PI3K potency and antiproliferative cell activity, relative to the corresponding monovalent inhibitor 11. Compound 27 also significantly blocks the PI3K signal pathway, induces cell cycle arrest in G1 phase, and inhibits colony formation and cell migration. Furthermore, compound 27 shows dose-dependent anticancer efficacies in a HGC-27 xenograft mice model. Overall, this work provides a possible strategy to discover novel PI3K inhibitors for the treatment of cancers.

Targeting Intracellular Antigens with pMHC-Binding Antibodies: A Phage Display Approach.

Antibodies that bind peptide-MHC (pMHC) complex in a manner akin to T cell receptor (TCR) have not only helped in understanding the mechanism of TCR-pMHC interactions in the context of T cell biology but also spurred considerable interest in recent years as potential cancer therapeutics. Traditional methods to generate such antibodies using hybridoma and B cell sorting technologies are sometimes inadequate, possibly due to the small contribution of peptide to the overall B cell epitope space on the surface of the pMHC complex (typical peptide MW = 1 kDa versus MHC MW = 45 kDa) and to the multiple efficiency limiting steps inherent in these methods. In this chapter we describe phage display approaches, including a cell panning strategy, for the rapid generation of such antibodies with high specificity and affinity.

Nuclear lamin facilitates collective border cell invasion into confined spaces in vivo.

Cells migrate collectively through confined environments during development and cancer metastasis. The nucleus, a stiff organelle, impedes single cells from squeezing into narrow channels within artificial environments. However, how nuclei affect collective migration into compact tissues is unknown. Here, we use border cells in the fly ovary to study nuclear dynamics in collective, confined in vivo migration. Border cells delaminate from the follicular epithelium and squeeze into tiny spaces between cells called nurse cells. The lead cell nucleus transiently deforms within the lead cell protrusion, which then widens. The nuclei of follower cells deform less. Depletion of the Drosophila B-type lamin, Lam, compromises nuclear integrity, hinders expansion of leading protrusions, and impedes border cell movement. In wildtype, cortical myosin II accumulates behind the nucleus and pushes it into the protrusion, whereas in Lam-depleted cells, myosin accumulates but does not move the nucleus. These data suggest that the nucleus stabilizes lead cell protrusions, helping to wedge open spaces between nurse cells.

Associative gene networks reveal novel candidates important for ADHD and dyslexia comorbidity.

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is commonly associated with developmental dyslexia (DD), which are both prevalent and complicated pediatric neurodevelopmental disorders that have a significant influence on children's learning and development. Clinically, the comorbidity incidence of DD and ADHD is between 25 and 48%. Children with DD and ADHD may have more severe cognitive deficiencies, a poorer level of schooling, and a higher risk of social and emotional management disorders. Furthermore, patients with this comorbidity are frequently treated for a single condition in clinical settings, and the therapeutic outcome is poor. The development of effective treatment approaches against these diseases is complicated by their comorbidity features. This is often a major problem in diagnosis and treatment. In this study, we developed bioinformatical methodology for the analysis of the comorbidity of these two diseases. As such, the search for candidate genes related to the comorbid conditions of ADHD and DD can help in elucidating the molecular mechanisms underlying the comorbid condition, and can also be useful for genotyping and identifying new drug targets. RESULTS: Using the ANDSystem tool, the reconstruction and analysis of gene networks associated with ADHD and dyslexia was carried out. The gene network of ADHD included 599 genes/proteins and 148,978 interactions, while that of dyslexia included 167 genes/proteins and 27,083 interactions. When the ANDSystem and GeneCards data were combined, a total of 213 genes/proteins for ADHD and dyslexia were found. An approach for ranking genes implicated in the comorbid condition of the two diseases was proposed. The approach is based on ten criteria for ranking genes by their importance, including relevance scores of association between disease and genes, standard methods of gene prioritization, as well as original criteria that take into account the characteristics of an associative gene network and the presence of known polymorphisms in the analyzed genes. Among the top 20 genes with the highest priority DRD2, DRD4, CNTNAP2 and GRIN2B are mentioned in the literature as directly linked with the comorbidity of ADHD and dyslexia. According to the proposed approach, the genes OPRM1, CHRNA4 and SNCA had the highest priority in the development of comorbidity of these two diseases. Additionally, it was revealed that the most relevant genes are involved in biological processes related to signal transduction, positive regulation of transcription from RNA polymerase II promoters, chemical synaptic transmission, response to drugs, ion transmembrane transport, nervous system development, cell adhesion, and neuron migration. CONCLUSIONS: The application of methods of reconstruction and analysis of gene networks is a powerful tool for studying the molecular mechanisms of comorbid conditions. The method put forth to rank genes by their importance for the comorbid condition of ADHD and dyslexia was employed to predict genes that play key roles in the development of the comorbid condition. The results can be utilized to plan experiments for the identification of novel candidate genes and search for novel pharmacological targets.