Exposure to angiotensin-converting enzyme inhibitors that cross the blood-brain barrier and the risk of dementia among People Living with HIV.

BACKGROUND: The decreased mortality of people living with HIV (PLWH) has revealed non-HIV-associated comorbidities such as neurocognitive disorders (e.g., dementia). There is an urgency to discover therapeutics to prevent or delay neurocognitive decline among PLWH. METHODS: The artificial intelligence platform Automatic Graph-mining And Transformer based Hypothesis Generation Approach (AGATHA) was utilized to seek potential drugs to be repurposed for the management of non-HIV-associated dementia. AGATHA revealed angiotensin-converting enzyme inhibitors that cross the blood-brain barrier (BBB ACEi) as a target for decreasing dementia. Subsequently, we conducted a retrospective study evaluating incident dementia using the VA Informatics and Computing Infrastructure (VINCI) evaluating ACE inhibitors. Cox proportional hazards models were fit and hazard ratios (HR) with corresponding 95% confidence intervals (CIs) are presented. FINDINGS: A total 9,419 PLWH exposed to an BBB ACE inhibitor (ACEi) and 8,831 PLWH unexposed demonstrated that PLWH exposed to BBB ACEi had a 21.4% (univariate) and 15.2% (multivariate) lower hazard of dementia. The propensity score matched analysis demonstrated a 14.3% lower hazard of incident dementia compared to BBB ACEi unexposed (HR 0.857, 95% CI 0.747-0.984). INTERPRETATION: An artificial intelligence-based literature mining system (AGATHA) was utilized to uncover a medication with potential to be repurposed. AGATHA demonstrated that BBB ACEi as a target for decreasing dementia among PLWH. Additionally, we conducted a retrospective study demonstrating a decrease in incident dementia among PLWH exposed to BBB ACEi. Future research is needed to explore further and understand the relationship of dementia among PLWH exposed to ACEi.

Heart failure with preserved ejection fraction in pigs causes shifts in post-transcriptional checkpoints.

Background: Left ventricular pressure overload (LVPO) can lead to heart failure with a preserved ejection fraction (HFpEF) and LV chamber stiffness (LV Kc) is a hallmark. This project tested the hypothesis that the development of HFpEF due to an LVPO stimulus, will alter post-transcriptional regulation, specifically microRNAs (miRs). Methods: LVPO was induced in pigs (n=9) by sequential ascending aortic cuff and age and weight matched pigs (n=6) served as controls. LV function was measured by echocardiography and LV Kc by speckle tracking. LV myocardial miRs were quantified using an 84 miR array. Treadmill testing and natriuretic peptide-A (NPPA) mRNA levels in controls and LVPO were performed (n=10, n=9, respectively). LV samples from LVPO and controls (n=6, respectively) were subjected to RNA sequencing. Results: LV mass and Kc increased by over 40% with LVPO (p<0.05). A total of 30 miRs shifted with LVPO of which 11 miRs correlated to LV Kc (p<0.05) which mapped to functional domains relevant to Kc such as fibrosis and calcium handling. LVPO resulted in reduced exercise tolerance (oxygen saturation, respiratory effort) and NPPA mRNA levels increased by 4-fold (p<0.05). RNA analysis identified several genes which mapped to specific miRs that were altered with LVPO. Conclusion: A specific set of miRs are changed in a large animal model consistent with the HFpEF phenotype, were related to LV stiffness properties and several miRs mapped to molecular pathways which may hold relevance in terms of prognosis and therapeutic targets.

AI-based mining of biomedical literature: Applications for drug repurposing for the treatment of dementia.

Neurodegenerative pathologies such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis, Multiple sclerosis, HIV-associated neurocognitive disorder, and others significantly affect individuals, their families, caregivers, and healthcare systems. While there are no cures yet, researchers worldwide are actively working on the development of novel treatments that have the potential to slow disease progression, alleviate symptoms, and ultimately improve the overall health of patients. Huge volumes of new scientific information necessitate new analytical approaches for meaningful hypothesis generation. To enable the automatic analysis of biomedical data we introduced AGATHA, an effective AI-based literature mining tool that can navigate massive scientific literature databases, such as PubMed. The overarching goal of this effort is to adapt AGATHA for drug repurposing by revealing hidden connections between FDA-approved medications and a health condition of interest. Our tool converts the abstracts of peer-reviewed papers from PubMed into multidimensional space where each gene and health condition are represented by specific metrics. We implemented advanced statistical analysis to reveal distinct clusters of scientific terms within the virtual space created using AGATHA-calculated parameters for selected health conditions and genes. Partial Least Squares Discriminant Analysis was employed for categorizing and predicting samples (122 diseases and 20889 genes) fitted to specific classes. Advanced statistics were employed to build a discrimination model and extract lists of genes specific to each disease class. Here we focus on drugs that can be repurposed for dementia treatment as an outcome of neurodegenerative diseases. Therefore, we determined dementia-associated genes statistically highly ranked in other disease classes. Additionally, we report a mechanism for detecting genes common to multiple health conditions. These sets of genes were classified based on their presence in biological pathways, aiding in selecting candidates and biological processes that are exploitable with drug repurposing.

Correlation Analysis of Genetic Mutations and Galectin Levels in Breast Cancer Patients.

Galectins are innate immune system regulators associated with disease progression in cancer. This paper aims to investigate the correlation between mutated cancer-critical genes and galectin levels in breast cancer patients to determine whether galectins and genetic profiles can be used as biomarkers for disease and potential therapy targets. Prisma Health Cancer Institute's Biorepository provided seventy-one breast cancer samples, including all four stages spanning the major molecular subtypes and histologies. Hotspot mutation statuses of cancer-critical genes were determined using multiplex PCR in tumor samples from the same patients by Precision Genetics and the University of South Carolina Functional Genomics Core Facility. The galectin-1, -3, and -9 levels in patients' sera were analyzed using Enzyme-linked Immunosorbent Assay (ELISA). An analysis was performed using JMP software to compare mean and median serum galectin levels between samples with and without specific cancer-critical genes, including pooled t-test, Wilcoxon Rank Sum Test, ANOVA, and Steel Dwass Test (α=0.05). Our analysis indicates that KIT mutations correlate with elevated serum levels of galectin-9 in patients with breast cancer. In patients with Luminal A subtype, FLT3 mutation correlates with lower serum galectin-1 and -9 levels and TP53 mutations correlate with higher serum galectin-3 levels. Patients with invasive ductal carcinoma had significantly higher serum galectin-3 levels than patients with ductal carcinoma in situ. Patients with both TP53 and PIK3CA mutations exhibit elevated serum galectin-3 levels, while patients with one or neither mutation show no significant difference in serum galectin-3 levels. In addition, metastatic breast cancer samples were more likely to have a KIT or PIK3CA mutation compared to primary breast cancer samples. The relationship between genetic mutations and galectin levels has the potential to identify appropriate candidates for combined therapy, targeting genetic mutations and galectins. Further understanding of the effect of genetic mutations and galectin levels on cancer progression and metastasis could aid in the search for biomarkers for breast cancer diagnosis, disease progression, and prognosis.

AI-based mining of biomedical literature: Applications for drug repurposing for the treatment of dementia.

Neurodegenerative pathologies such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis, Multiple sclerosis, HIV-associated neurocognitive disorder, and others significantly affect individuals, their families, caregivers, and healthcare systems. While there are no cures yet, researchers worldwide are actively working on the development of novel treatments that have the potential to slow disease progression, alleviate symptoms, and ultimately improve the overall health of patients. Huge volumes of new scientific information necessitate new analytical approaches for meaningful hypothesis generation. To enable the automatic analysis of biomedical data we introduced AGATHA, an effective AI-based literature mining tool that can navigate massive scientific literature databases, such as PubMed. The overarching goal of this effort is to adapt AGATHA for drug repurposing by revealing hidden connections between FDA-approved medications and a health condition of interest. Our tool converts the abstracts of peer-reviewed papers from PubMed into multidimensional space where each gene and health condition are represented by specific metrics. We implemented advanced statistical analysis to reveal distinct clusters of scientific terms within the virtual space created using AGATHA-calculated parameters for selected health conditions and genes. Partial Least Squares Discriminant Analysis was employed for categorizing and predicting samples (122 diseases and 20889 genes) fitted to specific classes. Advanced statistics were employed to build a discrimination model and extract lists of genes specific to each disease class. Here we focus on drugs that can be repurposed for dementia treatment as an outcome of neurodegenerative diseases. Therefore, we determined dementia-associated genes statistically highly ranked in other disease classes. Additionally, we report a mechanism for detecting genes common to multiple health conditions. These sets of genes were classified based on their presence in biological pathways, aiding in selecting candidates and biological processes that are exploitable with drug repurposing. Author Summary: This manuscript outlines our project involving the application of AGATHA, an AI-based literature mining tool, to discover drugs with the potential for repurposing in the context of neurocognitive disorders. The primary objective is to identify connections between approved medications and specific health conditions through advanced statistical analysis, including techniques like Partial Least Squares Discriminant Analysis (PLSDA) and unsupervised clustering. The methodology involves grouping scientific terms related to different health conditions and genes, followed by building discrimination models to extract lists of disease-specific genes. These genes are then analyzed through pathway analysis to select candidates for drug repurposing.

Suppression of HIV-TAT and cocaine-induced neurotoxicity and inflammation by cell penetrable itaconate esters.

HIV-associated neurological disorder (HAND) is a serious complication of HIV infection marked by neurotoxicity induced by viral proteins like Tat. Substance abuse exacerbates neurocognitive impairment in people living with HIV. There is an urgent need for therapeutic strategies to combat HAND comorbid with Cocaine Use Disorder (CUD). Our analysis of HIV and cocaine-induced transcriptomes in primary cortical cultures revealed significant overexpression of the macrophage-specific gene aconitate decarboxylase 1 (Acod1). The ACOD1 protein converts the tricarboxylic acid intermediate cis-aconitate into itaconate during the activation of inflammation. Itaconate then facilitates cytokine production and activates anti-inflammatory transcription factors, shielding macrophages from infection-induced cell death. However, the immunometabolic function of itaconate was unexplored in HIV and cocaine-exposed microglia. We assessed the potential of 4-octyl-itaconate (4OI), a cell-penetrable ester form of itaconate known for its anti-inflammatory properties. When primary cortical cultures exposed to Tat and cocaine were treated with 4OI, microglial cell number increased and the morphological altercations induced by Tat and cocaine were reversed. Microglial cells also appeared more ramified, resembling the quiescent microglia. 4OI treatment inhibited secretion of the proinflammatory cytokines IL-1α, IL-1ß, IL-6, and MIP1-α induced by Tat and cocaine. Transcriptome profiling determined that Nrf2 target genes were significantly activated in Tat and 4OI treated cultures relative to Tat alone. Further, genes associated with cytoskeleton dynamics in inflammatory microglia were downregulated by 4OI treatment. Together, the results strongly suggest 4-octyl-itaconate holds promise as a potential candidate for therapeutic development to treat HAND coupled with CUD comorbidities.

Glycosaminoglycan modifications of betaglycan regulate ectodomain shedding to fine-tune TGF-ß signaling responses in ovarian cancer.

In pathologies including cancer, aberrant Transforming Growth Factor-ß (TGF-ß) signaling exerts profound tumor intrinsic and extrinsic consequences. Intense clinical endeavors are underway to target this pathway. Central to the success of these interventions is pinpointing factors that decisively modulate the TGF-ß responses. Betaglycan/type III TGF-ß receptor (TßRIII), is an established co-receptor for the TGF-ß superfamily known to bind directly to TGF-ßs 1-3 and inhibin A/B. Betaglycan can be membrane-bound and also undergo ectodomain cleavage to produce soluble-betaglycan that can sequester its ligands. Its extracellular domain undergoes heparan sulfate and chondroitin sulfate glycosaminoglycan modifications, transforming betaglycan into a proteoglycan. We report the unexpected discovery that the heparan sulfate glycosaminoglycan chains on betaglycan are critical for the ectodomain shedding. In the absence of such glycosaminoglycan chains betaglycan is not shed, a feature indispensable for the ability of betaglycan to suppress TGF-ß signaling and the cells' responses to exogenous TGF-ß ligands. Using unbiased transcriptomics, we identified TIMP3 as a key inhibitor of betaglycan shedding thereby influencing TGF-ß signaling. Our results bear significant clinical relevance as modified betaglycan is present in the ascites of patients with ovarian cancer and can serve as a marker for predicting patient outcomes and TGF-ß signaling responses. These studies are the first to demonstrate a unique reliance on the glycosaminoglycan chains of betaglycan for shedding and influence on TGF-ß signaling responses. Dysregulated shedding of TGF-ß receptors plays a vital role in determining the response and availability of TGF-ßs', which is crucial for prognostic predictions and understanding of TGF-ß signaling dynamics.

Quantification of the immunometabolite protein modifications S-2-succinocysteine and 2,3-dicarboxypropylcysteine.

The tricarboxylic acid (TCA) cycle metabolite fumarate nonenzymatically reacts with the amino acid cysteine to form S-(2-succino)cysteine (2SC), referred to as protein succination. The immunometabolite itaconate accumulates during lipopolysaccharide (LPS) stimulation of macrophages and microglia. Itaconate nonenzymatically reacts with cysteine residues to generate 2,3-dicarboxypropylcysteine (2,3-DCP), referred to as protein dicarboxypropylation. Since fumarate and itaconate levels dynamically change in activated immune cells, the levels of both 2SC and 2,3-DCP reflect the abundance of these metabolites and their capacity to modify protein thiols. We generated ethyl esters of 2SC and 2,3-DCP from protein hydrolysates and used stable isotope dilution mass spectrometry to determine the abundance of these in LPS-stimulated Highly Aggressively Proliferating Immortalized (HAPI) microglia. To quantify the stoichiometry of the succination and dicarboxypropylation, reduced cysteines were alkylated with iodoacetic acid to form S-carboxymethylcysteine (CMC), which was then esterified. Itaconate-derived 2,3-DCP, but not fumarate-derived 2SC, increased in LPS-treated HAPI microglia. Stoichiometric measurements demonstrated that 2,3-DCP increased from 1.57% to 9.07% of total cysteines upon LPS stimulation. This methodology to simultaneously distinguish and quantify both 2SC and 2,3-DCP will have broad applications in the physiology of metabolic diseases. In addition, we find that available anti-2SC antibodies also detect the structurally similar 2,3-DCP, therefore "succinate moiety" may better describe the antigen recognized.NEW & NOTEWORTHY Itaconate and fumarate have roles as immunometabolites modulating the macrophage response to inflammation. Both immunometabolites chemically modify protein cysteine residues to modulate the immune response. Itaconate and fumarate levels change dynamically, whereas their stable protein modifications can be quantified by mass spectrometry. This method distinguishes itaconate and fumarate-derived protein modifications and will allow researchers to quantify their contributions in isolated cell types and tissues across a range of metabolic diseases.

Exposure to angiotensin-converting enzyme inhibitors that cross the blood-brain barrier and the risk of dementia among patients with human immunodeficiency virus.

More than one million people in the United States and over 38 million people worldwide are living with human immunodeficiency virus (HIV) infection. Antiretroviral therapy (ART) greatly improves the health of people living with HIV (PLWH); however, the increased life longevity of PLWH has revealed consequences of HIV-associated comorbidities. HIV can enter the brain and cause inflammation even in individuals with well-controlled HIV infection. The quality of life for PLWH can be compromised by cognitive deficits and memory loss, termed HIV-associated neurological disorders (HAND). HIV-associated dementia is a related but distinct diagnosis. Common causes of dementia in PLWH are similar to the general population and can affect cognition. There is an urgent need to identify treatments for the aging PWLH population. We previously developed AI-based biomedical literature mining systems to uncover a potential novel connection between HAND the renin-angiotensin system (RAAS), which is a pharmacological target for hypertension. RAAS-targeting anti-hypertensives are gaining attention for their protective benefits in several neurocognitive disorders. To our knowledge, the effect of RAAS-targeting drugs on the cognition of PLWH development of dementia has not previously been analyzed. We hypothesized that exposure to angiotensin-converting enzyme inhibitors (ACEi) that cross the blood brain barrier (BBB) reduces the risk/occurrence of dementia in PLWH. We report a retrospective cohort study of electronic health records (EHRs) to examine the proposed hypothesis using data from the United States Department of Veterans Affairs, in which a primary outcome of dementia was measured in controlled cohorts of patients exposed to BBB-penetrant ACEi versus those unexposed to BBB-penetrant ACEi. The results reveal a statistically significant reduction in dementia diagnosis for PLWH exposed to BBB-penetrant ACEi. These results suggest there is a potential protective effect of BBB ACE inhibitor exposure against dementia in PLWH that warrants further investigation.

Suppression of HIV and cocaine-induced neurotoxicity and inflammation by cell penetrable itaconate esters.

HIV-associated neurological disorder (HAND) is a serious complication of HIV infection, marked by neurotoxicity induced by viral proteins like Tat. Substance abuse exacerbates neurocognitive impairment in people living with HIV. There is an urgent need for effective therapeutic strategies to combat HAND comorbid with Cocaine Use Disorder (CUD). Our analysis of the HIV and cocaine-induced transcriptomes in primary cortical cultures revealed a significant overexpression of the macrophage-specific gene, aconitate decarboxylase 1 (Acod1), caused by the combined insults of HIV and cocaine. ACOD1 protein converts the tricarboxylic acid intermediate cis-aconitate into itaconate during the activation of inflammation. The itaconate produced facilitates cytokine production and subsequently activates anti-inflammatory transcription factors, shielding macrophages from infection-induced cell death. While the role of itaconate' in limiting inflammation has been studied in peripheral macrophages, its immunometabolic function remains unexplored in HIV and cocaine-exposed microglia. We assessed in this model system the potential of 4-octyl-itaconate (4OI), a cell-penetrable esterified form of itaconate known for its potent anti-inflammatory properties and potential therapeutic applications. We administered 4OI to primary cortical cultures exposed to Tat and cocaine. 4OI treatment increased the number of microglial cells in both untreated and Tat±Cocaine-treated cultures and also reversed the morphological altercations induced by Tat and cocaine. In the presence of 4OI, microglial cells also appeared more ramified, resembling the quiescent microglia. Consistent with these results, 4OI treatment inhibited the secretion of the proinflammatory cytokines IL-1α, IL-1ß, IL-6, and MIP1-α induced by Tat and cocaine. Transcriptome profiling further determined that Nrf2 target genes such as NAD(P)H quinone oxidoreductase 1 (Nqo1), Glutathione S-transferase Pi (Gstp1), and glutamate cysteine ligase catalytic (Gclc), were most significantly activated in Tat-4OI treated cultures, relative to Tat alone. Further, genes associated with cytoskeleton dynamics in inflammatory microglia were downregulated by 4OI treatment. Together, the results strongly suggest 4-octyl-itaconate holds promise as a potential candidate for therapeutic development aimed at addressing HAND coupled with CUD comorbidities.

Heparan sulfate modifications of betaglycan promote TIMP3-dependent ectodomain shedding to fine-tune TGF-ß signaling.

In pathologies such as cancer, aberrant Transforming Growth Factor-ß (TGF-ß) signaling exerts profound tumor intrinsic and extrinsic consequences. Intense clinical endeavors are underway to target this pivotal pathway. Central to the success of these interventions is pinpointing factors that decisively modulate the TGF-ß responses. Betaglycan/type III TGF-ß receptor (TßRIII), is an established co-receptor for the TGF-ß superfamily known to bind directly to TGF-ßs 1-3 and inhibin A/B. While betaglycan can be membrane-bound, it can also undergo ectodomain cleavage to produce soluble-betaglycan that can sequester its ligands. The extracellular domain of betaglycan undergoes heparan sulfate and chondroitin sulfate glycosaminoglycan modifications, transforming betaglycan into a proteoglycan. Here we report the unexpected discovery that the heparan sulfate modifications are critical for the ectodomain shedding of betaglycan. In the absence of such modifications, betaglycan is not shed. Such shedding is indispensable for the ability of betaglycan to suppress TGF-ß signaling and the cells' responses to exogenous TGF-ß ligands. Using unbiased transcriptomics, we identified TIMP3 as a key regulator of betaglycan shedding and thereby TGF-ß signaling. Our results bear significant clinical relevance as modified betaglycan is present in the ascites of patients with ovarian cancer and can serve as a marker for predicting patient outcomes and TGF-ß signaling responses. These studies are the first to demonstrate a unique reliance on the glycosaminoglycan modifications of betaglycan for shedding and influence on TGF-ß signaling responses. Dysregulated shedding of TGF-ß receptors plays a vital role in determining the response and availability of TGF-ßs', which is crucial for prognostic predictions and understanding of TGF-ß signaling dynamics.

CDK8 and CDK19: positive regulators of signal-induced transcription and negative regulators of Mediator complex proteins.

We have conducted a detailed transcriptomic, proteomic and phosphoproteomic analysis of CDK8 and its paralog CDK19, alternative enzymatic components of the kinase module associated with transcriptional Mediator complex and implicated in development and diseases. This analysis was performed using genetic modifications of CDK8 and CDK19, selective CDK8/19 small molecule kinase inhibitors and a potent CDK8/19 PROTAC degrader. CDK8/19 inhibition in cells exposed to serum or to agonists of NFκB or protein kinase C (PKC) reduced the induction of signal-responsive genes, indicating a pleiotropic role of Mediator kinases in signal-induced transcriptional reprogramming. CDK8/19 inhibition under basal conditions initially downregulated a small group of genes, most of which were inducible by serum or PKC stimulation. Prolonged CDK8/19 inhibition or mutagenesis upregulated a larger gene set, along with a post-transcriptional increase in the proteins comprising the core Mediator complex and its kinase module. Regulation of both RNA and protein expression required CDK8/19 kinase activities but both enzymes protected their binding partner cyclin C from proteolytic degradation in a kinase-independent manner. Analysis of isogenic cell populations expressing CDK8, CDK19 or their kinase-inactive mutants revealed that CDK8 and CDK19 have the same qualitative effects on protein phosphorylation and gene expression at the RNA and protein levels, whereas differential effects of CDK8 versus CDK19 knockouts were attributable to quantitative differences in their expression and activity rather than different functions.

Therapeutically targeting the consequences of HIV-1-associated gastrointestinal dysbiosis: Implications for neurocognitive and affective alterations.

Approximately 50 % of the individuals living with human immunodeficiency virus type 1 (HIV-1) are plagued by debilitating neurocognitive impairments (NCI) and/or affective alterations. Sizeable alterations in the composition of the gut microbiome, or gastrointestinal dysbiosis, may underlie, at least in part, the NCI, apathy, and/or depression observed in this population. Herein, two interrelated aims will be critically addressed, including: 1) the evidence for, and functional implications of, gastrointestinal microbiome dysbiosis in HIV-1 seropositive individuals; and 2) the potential for therapeutically targeting the consequences of this dysbiosis for the treatment of HIV-1-associated NCI and affective alterations. First, gastrointestinal microbiome dysbiosis in HIV-1 seropositive individuals is characterized by decreased alpha (α) diversity, a decreased relative abundance of bacterial species belonging to the Bacteroidetes phylum, and geographic-specific alterations in Bacillota (formerly Firmicutes) spp. Fundamentally, changes in the relative abundance of Bacteroidetes and Bacillota spp. may underlie, at least in part, the deficits in γ-aminobutyric acid and serotonin neurotransmission, as well as prominent synaptodendritic dysfunction, observed in this population. Second, there is compelling evidence for the therapeutic utility of targeting synaptodendritic dysfunction as a method to enhance neurocognitive function and improve motivational dysregulation in HIV-1. Further research is needed to determine whether the therapeutics enhancing synaptic efficacy exert their effects by altering the gut microbiome. Taken together, understanding gastrointestinal microbiome dysbiosis resulting from chronic HIV-1 viral protein exposure may afford insight into the mechanisms underlying HIV-1-associated neurocognitive and/or affective alterations; mechanisms which can be subsequently targeted via novel therapeutics.

Inhibition of CDK8/19 Mediator kinase potentiates HER2-targeting drugs and bypasses resistance to these agents in vitro and in vivo.

Breast cancers (BrCas) that overexpress oncogenic tyrosine kinase receptor HER2 are treated with HER2-targeting antibodies (such as trastuzumab) or small-molecule kinase inhibitors (such as lapatinib). However, most patients with metastatic HER2+ BrCa have intrinsic resistance and nearly all eventually become resistant to HER2-targeting therapy. Resistance to HER2-targeting drugs frequently involves transcriptional reprogramming associated with constitutive activation of different signaling pathways. We have investigated the role of CDK8/19 Mediator kinase, a regulator of transcriptional reprogramming, in the response of HER2+ BrCa to HER2-targeting drugs. CDK8 was in the top 1% of all genes ranked by correlation with shorter relapse-free survival among treated HER2+ BrCa patients. Selective CDK8/19 inhibitors (senexin B and SNX631) showed synergistic interactions with lapatinib and trastuzumab in a panel of HER2+ BrCa cell lines, overcoming and preventing resistance to HER2-targeting drugs. The synergistic effects were mediated in part through the PI3K/AKT/mTOR pathway and reduced by PI3K inhibition. Combination of HER2- and CDK8/19-targeting agents inhibited STAT1 and STAT3 phosphorylation at S727 and up-regulated tumor suppressor BTG2. The growth of xenograft tumors formed by lapatinib-sensitive or -resistant HER2+ breast cancer cells was partially inhibited by SNX631 alone and strongly suppressed by the combination of SNX631 and lapatinib, overcoming lapatinib resistance. These effects were associated with decreased tumor cell proliferation and altered recruitment of stromal components to the xenograft tumors. These results suggest potential clinical benefit of combining HER2- and CDK8/19-targeting drugs in the treatment of metastatic HER2+ BrCa.

Genomic variation in captive deer mouse (Peromyscus maniculatus) populations.

BACKGROUND: Deer mice (genus Peromyscus) are the most common rodents in North America. Despite the availability of reference genomes for some species, a comprehensive database of polymorphisms, especially in those maintained as living stocks and distributed to academic investigators, is missing. In the present study we surveyed two populations of P. maniculatus that are maintained at the Peromyscus Genetic Stock Center (PGSC) for polymorphisms across their 2.5 × 109 bp genome. RESULTS: High density of variation was identified, corresponding to one SNP every 55 bp for the high altitude stock (SM2) or 207 bp for the low altitude stock (BW) using snpEff (v4.3). Indels were detected every 1157 bp for BW or 311 bp for SM2. The average Watterson estimator for the BW and SM2 populations is 248813.70388 and 869071.7671 respectively. Some differences in the distribution of missense, nonsense and silent mutations were identified between the stocks, as well as polymorphisms in genes associated with inflammation (NFATC2), hypoxia (HIF1a) and cholesterol metabolism (INSIG1) and may possess value in modeling pathology. CONCLUSIONS: This genomic resource, in combination with the availability of P. maniculatus from the PGSC, is expected to promote genetic and genomic studies with this animal model.

Pharmacological inhibition of DEAD-Box RNA Helicase 3 attenuates stress granule assembly.

Stress granules (SGs) are non-membranous cytosolic protein-RNA aggregates that process mRNAs through stalled translation initiation in response to cellular stressors and in disease. DEAD-Box RNA helicase 3 (DDX3) is an active target of drug development for the treatment of viral infections, cancers, and neurodegenerative diseases. DDX3 plays a critical role in RNA metabolism, including SGs, but the role of DDX3 enzymatic activity in SG dynamics is not well understood. Here, we address this question by determining the effects of DDX3 inhibition on the dynamics of SG assembly and disassembly. We use two small molecule inhibitors of DDX3, RK33 and 16D, with distinct inhibitory mechanisms that target DDX3's ATPase activity and RNA helicase site, respectively. We find that both DDX3 inhibitors reduce the assembly of SGs, with a more pronounced reduction from RK-33. In contrast, both compounds only marginally affect the disassembly of SGs. RNA-mediated knockdown of DDX3 caused a similar reduction in SG assembly and minimal effect on SG disassembly. Collectively, these results reveal that the enzymatic activity of DDX3 is required for the assembly of SGs and pharmacological inhibition of DDX3 could be relevant for the treatment of SG-dependent pathologies.

A strategy for the identification of paracrine regulators of cancer cell migration.

We hypothesized that the correlation of the whole transcriptome with quantifiable phenotypes may unveil genes contributing to the regulation of the corresponding response. We tested this hypothesis in cultured fibroblasts exposed to diverse pharmacological and biological agents, to identify genes influencing chemoattraction of breast cancer cells. Our analyses revealed several genes that correlated, either positively or negatively with cell migration, suggesting that they may operate as activators or inhibitors of this process. Survey of the scientific literature showed that genes exhibiting positive or negative association with cell migration had frequently been linked to cancer and metastasis before, while those with minimal association were not. The current methodology may formulate the basis for the development of novel strategies linking genes to quantifiable phenotypes.

tRNAArg-Derived Fragments Can Serve as Arginine Donors for Protein Arginylation.

Arginyltransferase ATE1 mediates posttranslational arginylation and plays key roles in multiple physiological processes. ATE1 utilizes arginyl (Arg)-tRNAArg as the donor of Arg, putting this reaction into a direct competition with the protein synthesis machinery. Here, we address the question of ATE1- Arg-tRNAArg specificity as a potential mechanism enabling this competition in vivo. Using in vitro arginylation assays and Ate1 knockout models, we find that, in addition to full-length tRNA, ATE1 is also able to utilize short tRNAArg fragments that bear structural resemblance to tRNA-derived fragments (tRF), a recently discovered class of small regulatory non-coding RNAs with global emerging biological role. Ate1 knockout cells show a decrease in tRFArg generation and a significant increase in the ratio of tRNAArg:tRFArg compared with wild type, suggesting a functional link between tRFArg and arginylation. We propose that generation of physiologically important tRFs can serve as a switch between translation and protein arginylation.

Inhibition of the Dead Box RNA Helicase 3 Prevents HIV-1 Tat and Cocaine-Induced Neurotoxicity by Targeting Microglia Activation.

HIV-1 Associated Neurocognitive Disorder (HAND) is a common and clinically detrimental complication of HIV infection. Viral proteins, including Tat, released from infected cells, cause neuronal toxicity. Substance abuse in HIV-infected patients greatly influences the severity of neuronal damage. To repurpose small molecule inhibitors for anti-HAND therapy, we employed MOLIERE, an AI-based literature mining system that we developed. All human genes were analyzed and prioritized by MOLIERE to find previously unknown targets connected to HAND. From the identified high priority genes, we narrowed the list to those with known small molecule ligands developed for other applications and lacking systemic toxicity in animal models. To validate the AI-based process, the selective small molecule inhibitor of DDX3 helicase activity, RK-33, was chosen and tested for neuroprotective activity. The compound, previously developed for cancer treatment, was tested for the prevention of combined neurotoxicity of HIV Tat and cocaine. Rodent cortical cultures were treated with 6 or 60 ng/ml of HIV Tat and 10 or 25 µM of cocaine, which caused substantial toxicity. RK-33 at doses as low as 1 µM greatly reduced the neurotoxicity of Tat and cocaine. Transcriptome analysis showed that most Tat-activated transcripts are microglia-specific genes and that RK-33 blocks their activation. Treatment with RK-33 inhibits the Tat and cocaine-dependent increase in the number and size of microglia and the proinflammatory cytokines IL-6, TNF-α, MCP-1/CCL2, MIP-2, IL-1α and IL-1ß. These findings reveal that inhibition of DDX3 may have the potential to treat not only HAND but other neurodegenerative diseases. Graphical Abstract RK-33, selective inhibitor of Dead Box RNA helicase 3 (DDX3) protects neurons from combined Tat and cocaine neurotoxicity by inhibition of microglia activation and production of proinflammatory cytokines.

Identifying Cancers Impacted by CDK8/19.

CDK8 and CDK19 Mediator kinases are transcriptional co-regulators implicated in several types of cancer. Small-molecule CDK8/19 inhibitors have recently entered or are entering clinical trials, starting with breast cancer and acute myeloid leukemia (AML). To identify other cancers where these novel drugs may provide benefit, we queried genomic and transcriptomic databases for potential impact of CDK8, CDK19, or their binding partner CCNC. sgRNA analysis of a panel of tumor cell lines showed that most tumor types represented in the panel, except for some central nervous system tumors, were not dependent on these genes. In contrast, analysis of clinical samples for alterations in these genes revealed a high frequency of gene amplification in two highly aggressive subtypes of prostate cancer and in some cancers of the GI tract, breast, bladder, and sarcomas. Analysis of survival correlations identified a group of cancers where CDK8 expression correlated with shorter survival (notably breast, prostate, cervical cancers, and esophageal adenocarcinoma). In some cancers (AML, melanoma, ovarian, and others), such correlations were limited to samples with a below-median tumor mutation burden. These results suggest that Mediator kinases are especially important in cancers that are driven primarily by transcriptional rather than mutational changes and warrant an investigation of their role in additional cancer types.