My Recent Publications

Specific binding sites on Rhesus rotavirus capsid protein dictates the method of endocytosis inducing the murine model of biliary atresia

Tue, 2024-06-11 06:00

Am J Physiol Gastrointest Liver Physiol. 2024 Jun 11. doi: 10.1152/ajpgi.00308.2023. Online ahead of print.

ABSTRACT

Biliary atresia (BA) is the leading indication for pediatric liver transplantation. Rhesus rotavirus (RRV) induced murine BA develops an obstructive cholangiopathy that mirrors the human disease. We have previously demonstrated the "SRL" motif on RRV's VP4 protein binds to heat shock cognate 70 protein (Hsc70) facilitating entry into cholangiocytes. In this study, we analyzed how binding to Hsc70 affects viral endocytosis, intracellular trafficking, and uniquely activates the signaling pathway that induces murine BA. Inhibition of clathrin- and dynamin-mediated endocytosis in cholangiocytes following infection demonstrated blocking dynamin decreased the infectivity of RRV whereas clathrin inhibition had no effect. Blocking early endosome trafficking resulted in decreased viral titers of RRV while late endosome inhibition had no effect. Following infection, TLR3 expression and p-NF-κB levels increased in cholangiocytes, leading to increased release of CXCL9 and CXCL10. Infected mice knocked out for TLR3 had decreased levels of CXCL9 and CXCL10, resulting in reduced NK cell numbers. Human BA patients experienced an increase in CXCL10 levels, suggesting this as a possible pathway leading to biliary obstruction. Viruses that utilize Hsc70 for cell entry exploit a clathrin-independent pathway and traffic to the early recycling endosome uniquely activating NF-κB through TLR3, leading to the release of CXCL9 and CXCL10, and inducing NK cell recruitment. These results define how the "SRL" peptide found on RRV's VP4 protein modulates viral trafficking, inducing the host response leading to bile duct obstruction.

PMID:38860860 | DOI:10.1152/ajpgi.00308.2023

Application of artificial intelligence and machine learning in drug repurposing

Fri, 2024-05-24 06:00

Prog Mol Biol Transl Sci. 2024;205:171-211. doi: 10.1016/bs.pmbts.2024.03.030. Epub 2024 Mar 31.

ABSTRACT

The purpose of drug repurposing is to leverage previously approved drugs for a particular disease indication and apply them to another disease. It can be seen as a faster and more cost-effective approach to drug discovery and a powerful tool for achieving precision medicine. In addition, drug repurposing can be used to identify therapeutic candidates for rare diseases and phenotypic conditions with limited information on disease biology. Machine learning and artificial intelligence (AI) methodologies have enabled the construction of effective, data-driven repurposing pipelines by integrating and analyzing large-scale biomedical data. Recent technological advances, especially in heterogeneous network mining and natural language processing, have opened up exciting new opportunities and analytical strategies for drug repurposing. In this review, we first introduce the challenges in repurposing approaches and highlight some success stories, including those during the COVID-19 pandemic. Next, we review some existing computational frameworks in the literature, organized on the basis of the type of biomedical input data analyzed and the computational algorithms involved. In conclusion, we outline some exciting new directions that drug repurposing research may take, as pioneered by the generative AI revolution.

PMID:38789178 | DOI:10.1016/bs.pmbts.2024.03.030

SEMA3B inhibits TGFβ-induced extracellular matrix protein production and its reduced levels are associated with a decline in lung function in IPF

Mon, 2024-04-22 06:00

Am J Physiol Cell Physiol. 2024 Apr 22. doi: 10.1152/ajpcell.00681.2023. Online ahead of print.

ABSTRACT

Idiopathic pulmonary fibrosis (IPF) is marked by the activation of fibroblasts, leading to excessive production and deposition of extracellular matrix (ECM) within the lung parenchyma. Despite the pivotal role of ECM overexpression in IPF, potential negative regulators of ECM production in fibroblasts have yet to be identified. Semaphorin class 3B (SEMA3B), a secreted protein highly expressed in lung tissues, has established roles in axonal guidance and tumor suppression. However, the role of SEMA3B in ECM production by fibroblasts in the pathogenesis of IPF remains unexplored. Here, we show the downregulation of SEMA3B and its cognate binding receptor, neuropilin 1 (NRP1) in IPF lungs compared with healthy controls. Notably, the reduced expression of SEMA3B and NRP1 is associated with a decline in lung function in IPF. The downregulation of SEMA3B and NRP1 transcripts was validated in the lung tissues of patients with IPF, and two alternative mouse models of pulmonary fibrosis. In addition, we show that TGFβ functions as a negative regulator of SEMA3B and NRP1 expression in lung fibroblasts. Furthermore, we demonstrate the anti-fibrotic effects of SEMA3B against TGFβ-induced ECM production in IPF lung fibroblasts. Overall, our findings uncovered a novel role of SEMA3B in the pathogenesis of pulmonary fibrosis and provided novel insights into modulating the SEMA3B-NRP1 axis to attenuate pulmonary fibrosis.

PMID:38646784 | DOI:10.1152/ajpcell.00681.2023

Neuroinflammation underlies the development of social stress induced cognitive deficit in sickle cell disease

Thu, 2024-02-08 06:00

bioRxiv. 2024 Jan 25:2024.01.24.577074. doi: 10.1101/2024.01.24.577074. Preprint.

ABSTRACT

Cognitive deficit is a debilitating complication of SCD with multifactorial pathobiology. Here we show that neuroinflammation and dysregulation in lipidomics and transcriptomics profiles are major underlying mechanisms of social stress-induced cognitive deficit in SCD. Townes sickle cell (SS) mice and controls (AA) were exposed to social stress using the repeat social defeat (RSD) paradigm concurrently with or without treatment with minocycline. Mice were tested for cognitive deficit using novel object recognition (NOR) and fear conditioning (FC) tests. SS mice exposed to RSD without treatment had worse performance on cognitive tests compared to SS mice exposed to RSD with treatment or to AA controls, irrespective of their RSD or treatment disposition. Additionally, compared to SS mice exposed to RSD with treatment, SS mice exposed to RSD without treatment had significantly more cellular evidence of neuroinflammation coupled with a significant shift in the differentiation of neural progenitor cells towards astrogliogenesis. Additionally, brain tissue from SS mice exposed to RSD was significantly enriched for genes associated with blood-brain barrier dysfunction, neuron excitotoxicity, inflammation, and significant dysregulation in sphingolipids important to neuronal cell processes. We demonstrate in this study that neuroinflammation and lipid dysregulation are potential underlying mechanisms of social stress-related cognitive deficit in SS mice.

KEY POINTS: Neuroinflammation and lipid dysfunction are potential underlying mechanisms of social stress-related cognitive deficit in SCD patients.Mitigating or ameliorating the impact of cognitive deficits in SCD needs to consider the biological changes already created by exposure to social stress.

NOVELTY OF OUR FINDINGS: We show for the first time, that neuroinflammation along with changes in the brain lipidome and transcriptome, are underlying biological mechanism contributing to the development and potentially progression of cognitive impairment among sickle cell patients. These findings also provide for the first time, a mechanistic basis for an earlier reported observation of a higher likelihood of having lower intelligence quotient scores among children with sickle cell disease exposed to social stress in the form of low parental socioeconomic status.

PMID:38328164 | PMC:PMC10849745 | DOI:10.1101/2024.01.24.577074

Perturbations of Glutathione and Sphingosine Metabolites in Port Wine Birthmark Patient-Derived Induced Pluripotent Stem Cells

Wed, 2023-09-27 06:00

Metabolites. 2023 Aug 31;13(9):983. doi: 10.3390/metabo13090983.

ABSTRACT

Port Wine Birthmarks (PWBs) are a congenital vascular malformation on the skin, occurring in 1-3 per 1000 live births. We have recently generated PWB-derived induced pluripotent stem cells (iPSCs) as clinically relevant disease models. The metabolites associated with the pathological phenotypes of PWB-derived iPSCs are unknown, and so we aim to explore them in this study. Metabolites were separated by ultra-performance liquid chromatography and screened with electrospray ionization mass spectrometry. Orthogonal partial least-squares discriminant, multivariate, and univariate analyses were used to identify differential metabolites (DMs). KEGG analysis was used to determine the enrichment of metabolic pathways. A total of 339 metabolites was identified. There were 22 DMs, among which nine were downregulated-including sphingosine-and 13 were upregulated, including glutathione in PWB iPSCs, as compared to controls. Pathway enrichment analysis confirmed the upregulation of glutathione and the downregulation of sphingolipid metabolism in PWB-derived iPSCs as compared to normal ones. We next examined the expression patterns of the key molecules associated with glutathione metabolism in PWB lesions. We found that hypoxia-inducible factor 1α (HIF1α), glutathione S-transferase Pi 1 (GSTP1), γ-glutamyl transferase 7 (GGT7), and glutamate cysteine ligase modulatory subunit (GCLM) were upregulated in PWB vasculatures as compared to blood vessels in normal skin. Other significantly affected metabolic pathways in PWB iPSCs included pentose and glucuronate interconversions; amino sugar and nucleotide sugars; alanine, aspartate, and glutamate; arginine, purine, D-glutamine, and D-glutamate; arachidonic acid, glyoxylate, and dicarboxylate; nitrogen, aminoacyl-tRNA biosynthesis, pyrimidine, galactose, ascorbate, and aldarate; and starch and sucrose. Our data demonstrated that there were perturbations in sphingolipid and cellular redox homeostasis in PWB vasculatures, which could facilitate cell survival and pathological progression. Our data implied that the upregulation of glutathione could contribute to laser-resistant phenotypes in some PWB vasculatures.

PMID:37755263 | DOI:10.3390/metabo13090983

BRD9-SMAD2/3 orchestrates stemness and tumorigenesis in pancreatic ductal adenocarcinoma

Fri, 2023-09-22 06:00

Gastroenterology. 2023 Sep 20:S0016-5085(23)05012-6. doi: 10.1053/j.gastro.2023.09.021. Online ahead of print.

ABSTRACT

BACKGROUND AND AIMS: The dismal prognosis of pancreatic ductal adenocarcinoma (PDAC) is linked to the presence of pancreatic cancer stem-like cells (CSCs) that respond poorly to current chemotherapy regimens. The epigenetic mechanisms regulating CSCs are currently insufficiently understood which hampers the development of novel strategies for eliminating CSCs.

METHODS: By small molecule compound screening targeting 142 epigenetic enzymes, we identified that bromodomain-containing protein BRD9, a component of the BAF histone remodelling complex, is a key chromatin regulator to orchestrate the stemness of pancreatic CSCs via cooperating with the TGFβ/Activin-SMAD2/3 signalling pathway.

RESULTS: Inhibition and genetic ablation of BRD9 block the self-renewal, cell cycle entry into G0 phase and invasiveness of CSCs, and improve the sensitivity of CSCs to Gemcitabine treatment. In addition, pharmacological inhibition of BRD9 significantly reduced the tumorigenesis in patient-derived xenografts mouse models and eliminated CSCs in tumours from pancreatic cancer patients. Mechanistically, inhibition of BRD9 disrupts enhancer-promoter looping and transcription of stemness genes in CSCs.

CONCLUSIONS: Collectively, the data suggest BRD9 as a novel therapeutic target for PDAC treatment via modulation of CSC stemness.

PMID:37739089 | DOI:10.1053/j.gastro.2023.09.021

Endothelial cells differentiated from patient dermal fibroblast-derived induced pluripotent stem cells resemble vascular malformations of Port Wine Birthmark

Wed, 2023-09-06 06:00

Br J Dermatol. 2023 Sep 6:ljad330. doi: 10.1093/bjd/ljad330. Online ahead of print.

NO ABSTRACT

PMID:37672656 | DOI:10.1093/bjd/ljad330

Supporting materials: Endothelial cells differentiated from patient dermal fibroblast-derived induced pluripotent stem cells resemble vascular malformations of Port Wine Birthmark

Mon, 2023-09-04 06:00

bioRxiv. 2023 Aug 24:2023.07.02.547408. doi: 10.1101/2023.07.02.547408. Preprint.

ABSTRACT

BACKGROUND: Port wine birthmark (PWB) is a congenital vascular malformation resulting from developmentally defective endothelial cells (ECs). Developing clinically relevant disease models for PWB studies is currently an unmet need.

OBJECTIVE: Our study aims to generate PWB-derived induced pluripotent stem cells (iPSCs) and iPSC-derived ECs that preserve disease-related phenotypes.

METHODS: PWB iPSCs were generated by reprogramming lesional dermal fibroblasts and differentiated into ECs. RNA-seq was performed to identify differentially expressed genes (DEGs) and enriched pathways. The functional phenotypes of iPSC-derived ECs were characterized by capillary-like structure (CLS) formation in vitro and Geltrex plug-in assay in vivo .

RESULTS: Human PWB and control iPSC lines were generated through reprogramming of dermal fibroblasts by introducing the "Yamanaka factors" (Oct3/4, Sox2, Klf4, c-Myc) into them; the iPSCs were successfully differentiated into ECs. These iPSCs and their derived ECs were validated by expression of a series of stem cell and EC biomarkers, respectively. PWB iPSC-derived ECs showed impaired CLS in vitro with larger perimeters and thicker branches as compared to control iPSC-derived ECs. In the plug-in assay, perfused human vasculature formed by PWB iPSC- derived ECs showed bigger perimeters and greater densities than those formed by control iPSC- derived ECs in severe combined immune deficient (SCID) mice. The transcriptome analysis showed that dysregulated pathways of stem cell differentiation, Hippo, Wnt, and focal adhesion persisted through differentiation of PWB iPSCs to ECs. Functional enrichment analysis showed that Hippo and Wnt pathway-related PWB DEGs are enriched for vasculature development, tube morphology, endothelium development, and EC differentiation. Further, members of the zinc finger (ZNF) gene family were overrepresented among the DEGs in PWB iPSCs. ZNF DEGs confer significant functions in transcriptional regulation, chromatin remodeling, protein ubiquitination, and retinoic acid receptor signaling. Furthermore, NF-kappa B, TNF, MAPK, and cholesterol metabolism pathways were dysregulated in PWB ECs as readouts of impaired differentiation.

CONCLUSIONS: PWB iPSC-derived ECs render a novel and clinically-relevant disease model by retaining pathological phenotypes. Our data demonstrate multiple pathways, such as Hippo and Wnt, NF-kappa B, TNF, MAPK, and cholesterol metabolism, are dysregulated, which may contribute to the development of differentiation-defective ECs in PWB.

BULLETED STATEMENTS: What is already known about this topic?: Port Wine Birthmark (PWB) is a congenital vascular malformation with an incidence rate of 0.1 - 0.3 % per live births.PWB results from developmental defects in the dermal vasculature; PWB endothelial cells (ECs) have differentiational impairments.Pulse dye laser (PDL) is currently the preferred treatment for PWB; unfortunately, the efficacy of PDL treatment of PWB has not improved over the past three decades.What does this study add?: Induced pluripotent stem cells (iPSCs) were generated from PWB skin fibroblasts and differentiated into ECs.PWB ECs recapitulated their pathological phenotypes such as forming enlarged blood vessels in vitro and in vivo.Hippo and Wnt pathways were dysregulated in PWB iPSCs and ECs.Zinc-finger family genes were overrepresented among the differentially expressed genes in PWB iPSCs.Dysregulated NF-kappa B, TNF, MAPK, and cholesterol metabolism pathways were enriched in PWB ECs.What is the translational message?: Targeting Hippo and Wnt pathways and Zinc-finger family genes could restore the physiological differentiation of ECs.Targeting NF-kappa B, TNF, MAPK, and cholesterol metabolism pathways could mitigate the pathological progression of PWB.These mechanisms may lead to the development of paradigm-shifting therapeutic interventions for PWB.

PMID:37662218 | PMC:PMC10473620 | DOI:10.1101/2023.07.02.547408

Perturbations of glutathione and sphingosine metabolites in Port Wine Birthmark patient-derived induced pluripotent stem cells

Fri, 2023-07-28 06:00

bioRxiv. 2023 Jul 19:2023.07.18.549581. doi: 10.1101/2023.07.18.549581. Preprint.

ABSTRACT

Port Wine Birthmark (PWB) is a congenital vascular malformation in the skin, occurring in 1-3 per 1,000 live births. We recently generated PWB-derived induced pluripotent stem cells (iPSCs) as clinically relevant disease models. The metabolites associated with the pathological phenotypes of PWB-derived iPSCs are unknown, which we aimed to explore in this study. Metabolites were separated by ultra-performance liquid chromatography and were screened with electrospray ionization mass spectrometry. Orthogonal partial least-squares discriminant analysis, multivariate and univariate analysis were used to identify differential metabolites (DMs). KEGG analysis was used for the enrichment of metabolic pathways. A total of 339 metabolites were identified. There were 22 DMs confirmed with 9 downregulated DMs including sphingosine and 13 upregulated DMs including glutathione in PWB iPSCs as compared to controls. Pathway enrichment analysis confirmed the upregulation of glutathione and downregulation of sphingolipid metabolism in PWB-derived iPSCs as compared to normal ones. We next examined the expression patterns of the key factors associated with glutathione metabolism in PWB lesions. We found that hypoxia-inducible factor 1α (HIF1α), glutathione S-transferase Pi 1 (GSTP1), γ-glutamyl transferase 7 (GGT7), and glutamate cysteine ligase modulatory subunit (GCLM) were upregulated in PWB vasculatures as compared to blood vessels in normal skins. Our data demonstrate that there are perturbations in sphingolipid and cellular redox homeostasis in the PWB vasculature, which may facilitate cell survival and pathological progression. Our data imply that upregulation of glutathione may contribute to laser-resistant phenotypes in the PWB vasculature.

PMID:37503303 | PMC:PMC10370126 | DOI:10.1101/2023.07.18.549581

Mucosal transcriptomics highlight lncRNAs implicated in ulcerative colitis, Crohn disease, and celiac disease

Thu, 2023-06-01 06:00

JCI Insight. 2023 Jun 1:e170181. doi: 10.1172/jci.insight.170181. Online ahead of print.

ABSTRACT

Ulcerative colitis (UC), Crohn's disease (CD), and celiac disease are prevalent intestinal inflammatory disorders with non-satisfactory therapeutic interventions. Analyzing patient data-driven cohorts can highlight disease pathways and new targets for interventions. Long non-coding RNAs (lncRNAs) are attractive candidates as they are readily targetable by RNA therapeutics, show relative cell-specific expression, and play key cellular functions. Uniformly analyzing gut mucosal transcriptomics from 696 subjects, we highlight lncRNA expression along the gastrointestinal (GI) tract, demonstrating that in control samples, lncRNAs have a more location-specific expression in comparison to protein-coding genes. We defined dysregulation of lncRNAs in treatment-naïve UC, CD, and celiac diseases using independent test and validation cohorts. Using the PROTECT inception UC cohort, we define and prioritize lncRNA linked with UC severity and prospective outcomes, and highlight lncRNAs linked with gut microbes previously implicated in mucosal homeostasis. HNF1A-AS1 lncRNA was reduced in all 3 conditions and was further reduced in more severe UC form. Similarly, the reduction of HNF1A-AS1 ortholog in mice gut epithelial showed higher sensitivity to dextran sodium sulfate-induced colitis which was coupled with alteration in the gut microbial community. These analyses highlight prioritized dysregulated lncRNAs that can guide future preclinical studies for testing them as novel potential targets.

PMID:37261910 | DOI:10.1172/jci.insight.170181

Relationships between gene expression and behavior in mice in response to systemic modulation of the O-GlcNAcylation pathway

Tue, 2023-05-02 06:00

J Neurochem. 2023 May 2. doi: 10.1111/jnc.15835. Online ahead of print.

ABSTRACT

Enhancing protein O-GlcNAcylation by pharmacological inhibition of the enzyme O-GlcNAcase (OGA), which removes the O-GlcNAc modification from proteins, has been explored in mouse models of amyloid-beta and tau pathology. However, the O-GlcNAcylation-dependent link between gene expression and neurological behavior remains to be explored. Using chronic administration of Thiamet G (TG, an OGA inhibitor) in vivo, we used a protocol designed to relate behavior with the transcriptome and selected biochemical parameters from the cortex of individual animals. TG-treated mice showed improved working memory as measured using a Y-maze test. RNA sequencing analysis revealed 151 top differentially expressed genes with a Log2fold change > 0.33 and adjusted p-value < 0.05. Top TG-dependent upregulated genes were related to learning, cognition, and behavior, while top downregulated genes were related to IL-17 signaling, inflammatory response, and chemotaxis. Additional pathway analysis uncovered 3 pathways involving gene expression including 14 cytochrome c oxidase subunits/regulatory components, chaperones, or assembly factors, and 5 mTOR (mechanistic target of rapamycin) signaling factors. Multivariate Kendall correlation analyses of behavioral tests and the top TG-dependent differentially expressed genes revealed 91 statistically significant correlations in saline-treated mice and 70 statistically significant correlations in TG-treated mice. These analyses provide a network regulation landscape that is important in relating the transcriptome to behavior and the potential impact of the O-GlcNAC pathway.

PMID:37129420 | DOI:10.1111/jnc.15835

A comparison of anatomic and cellular transcriptome structures across 40 human brain diseases

Thu, 2023-04-20 06:00

PLoS Biol. 2023 Apr 20;21(4):e3002058. doi: 10.1371/journal.pbio.3002058. eCollection 2023 Apr.

ABSTRACT

Genes associated with risk for brain disease exhibit characteristic expression patterns that reflect both anatomical and cell type relationships. Brain-wide transcriptomic patterns of disease risk genes provide a molecular-based signature, based on differential co-expression, that is often unique to that disease. Brain diseases can be compared and aggregated based on the similarity of their signatures which often associates diseases from diverse phenotypic classes. Analysis of 40 common human brain diseases identifies 5 major transcriptional patterns, representing tumor-related, neurodegenerative, psychiatric and substance abuse, and 2 mixed groups of diseases affecting basal ganglia and hypothalamus. Further, for diseases with enriched expression in cortex, single-nucleus data in the middle temporal gyrus (MTG) exhibits a cell type expression gradient separating neurodegenerative, psychiatric, and substance abuse diseases, with unique excitatory cell type expression differentiating psychiatric diseases. Through mapping of homologous cell types between mouse and human, most disease risk genes are found to act in common cell types, while having species-specific expression in those types and preserving similar phenotypic classification within species. These results describe structural and cellular transcriptomic relationships of disease risk genes in the adult brain and provide a molecular-based strategy for classifying and comparing diseases, potentially identifying novel disease relationships.

PMID:37079537 | DOI:10.1371/journal.pbio.3002058

A systems approach points to a therapeutic role for retinoids in asparaginase-associated pancreatitis

Wed, 2023-03-15 06:00

Sci Transl Med. 2023 Mar 15;15(687):eabn2110. doi: 10.1126/scitranslmed.abn2110. Epub 2023 Mar 15.

ABSTRACT

Among drug-induced adverse events, pancreatitis is life-threatening and results in substantial morbidity. A prototype example is the pancreatitis caused by asparaginase, a crucial drug used to treat acute lymphoblastic leukemia (ALL). Here, we used a systems approach to identify the factors affecting asparaginase-associated pancreatitis (AAP). Connectivity Map analysis of the transcriptomic data showed that asparaginase-induced gene signatures were potentially reversed by retinoids (vitamin A and its analogs). Analysis of a large electronic health record database (TriNetX) and the U.S. Federal Drug Administration Adverse Events Reporting System demonstrated a reduction in AAP risk with concomitant exposure to vitamin A. Furthermore, we performed a global metabolomic screening of plasma samples from 24 individuals with ALL who developed pancreatitis (cases) and 26 individuals with ALL who did not develop pancreatitis (controls), before and after a single exposure to asparaginase. Screening from this discovery cohort revealed that plasma carotenoids were lower in the cases than in controls. This finding was validated in a larger external cohort. A 30-day dietary recall showed that the cases received less dietary vitamin A than the controls did. In mice, asparaginase administration alone was sufficient to reduce circulating and hepatic retinol. Based on these data, we propose that circulating retinoids protect against pancreatic inflammation and that asparaginase reduces circulating retinoids. Moreover, we show that AAP is more likely to develop with reduced dietary vitamin A intake. The systems approach taken for AAP provides an impetus to examine the role of dietary vitamin A supplementation in preventing or treating AAP.

PMID:36921036 | DOI:10.1126/scitranslmed.abn2110

BRD9-SMAD2/3 orchestrates stemness and tumorigenesis in pancreatic ductal adenocarcinoma

Mon, 2023-03-13 06:00

bioRxiv. 2023 Mar 2:2023.03.02.530770. doi: 10.1101/2023.03.02.530770. Preprint.

ABSTRACT

The dismal prognosis of pancreatic ductal adenocarcinoma (PDAC) is linked to the presence of pancreatic cancer stem-like cells (CSCs) that respond poorly to current chemotherapy regimens. By small molecule compound screening targeting 142 epigenetic enzymes, we identified that bromodomain-containing protein BRD9, a component of the BAF histone remodelling complex, is a key chromatin regulator to orchestrate the stemness of pancreatic CSCs via cooperating with the TGFβ/Activin-SMAD2/3 signalling pathway. Inhibition and genetic ablation of BDR9 block the self-renewal, cell cycle entry into G0 phase and invasiveness of CSCs, and improve the sensitivity of CSCs to gemcitabine treatment. In addition, pharmacological inhibition of BRD9 significantly reduced the tumorigenesis in patient-derived xenografts mouse models and eliminated CSCs in tumours from pancreatic cancer patients. Mechanistically, inhibition of BRD9 disrupts enhancer-promoter looping and transcription of stemness genes in CSCs. Collectively, the data suggest BRD9 as a novel therapeutic target for PDAC treatment via modulation of CSC stemness.

PMID:36909530 | PMC:PMC10002796 | DOI:10.1101/2023.03.02.530770

Transcriptome analysis in acute gastrointestinal graft-versus host disease reveals a unique signature in children and shared biology with pediatric inflammatory bowel disease

Thu, 2023-02-02 06:00

Haematologica. 2023 Feb 2. doi: 10.3324/haematol.2022.282035. Online ahead of print.

ABSTRACT

We performed transcriptomic analyses on freshly frozen (n=21) and paraffin embedded (n=35) gastrointestinal (GI)biopsies from children with and without acute GI graft versus host disease (GVHD) to study differential gene expressions. We identified 164 significant genes, 141 upregulated and 23 downregulated, in acute GVHD from freshy frozen biopsies. CHI3L1 was the top differentially expressed gene in acute GVHD, involved in macrophage recruitment and bacterial adhesion. Mitochondrial genes were among the top downregulated genes. Immune deconvolution identified a macrophage cellular signature. Weighted gene co-expression network analysis showed enrichment of genes in the ERK1/2 cascade. Transcriptome data from 206 ulcerative colitis (UC) patients were included to uncover genes and pathways shared between GVHD and UC. Comparison with the UC transcriptome showed both shared and distinct pathways. Both UC and GVHD transcriptomes shared an innate antimicrobial signature and FCγ1RA/CD64 was upregulated in both acute GVHD (log fold increase 1.7, p=0.001) and UC. Upregulation of the ERK1/2 cascade pathway was specific to GVHD. We performed additional experiments to confirm transcriptomics. Firstly, we examined phosphorylation of ERK (pERK) by immunohistochemistry on GI biopsies (acute GVHD n=10, no GVHD n=10). pERK staining was increased in acute GVHD biopsies compared to biopsies without acute GVHD (p= 0.001). Secondly, plasma CD64, measured by ELISA (n=85) was elevated in acute GI GVHD (p.

PMID:36727399 | DOI:10.3324/haematol.2022.282035

Combination of esomeprazole and pirfenidone enhances antifibrotic efficacy in vitro and in a mouse model of TGFβ-induced lung fibrosis

Wed, 2022-11-30 06:00

Sci Rep. 2022 Nov 30;12(1):20668. doi: 10.1038/s41598-022-24985-x.

ABSTRACT

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease of unknown etiology. Currently, pirfenidone and nintedanib are the only FDA-approved drugs for the treatment of IPF and are now the standard of care. This is a significant step in slowing down the progression of the disease. However, the drugs are unable to stop or reverse established fibrosis. Several retrospective clinical studies indicate that proton pump inhibitors (PPIs; FDA-approved to treat gastroesophageal reflux) are associated with favorable outcomes in patients with IPF, and emerging preclinical studies report that PPIs possess antifibrotic activity. In this study, we evaluated the antifibrotic efficacy of the PPI esomeprazole when combined with pirfenidone in vitro and in vivo. In cell culture studies of IPF lung fibroblasts, we assessed the effect of the combination on several fibrosis-related biological processes including TGFβ-induced cell proliferation, cell migration, cell contraction, and collagen production. In an in vivo study, we used mouse model of TGFβ-induced lung fibrosis to evaluate the antifibrotic efficacy of esomeprazole/pirfenidone combination. We also performed computational studies to understand the molecular mechanisms by which esomeprazole and/or pirfenidone regulate lung fibrosis. We found that esomeprazole significantly enhanced the anti-proliferative effect of pirfenidone and favorably modulated TGFβ-induced cell migration and contraction of collagen gels. We also found that the combination significantly suppressed collagen production in response to TGFβ in comparison to pirfenidone monotherapy. In addition, our animal study demonstrated that the combination therapy effectively inhibited the differentiation of lung fibroblasts into alpha smooth muscle actin (αSMA)-expressing myofibroblasts to attenuate the progression of lung fibrosis. Finally, our bioinformatics study of cells treated with esomeprazole or pirfenidone revealed that the drugs target several extracellular matrix (ECM) related pathways with esomeprazole preferentially targeting collagen family members while pirfenidone targets the keratins. In conclusion, our cell biological, computational, and in vivo studies show that the PPI esomeprazole enhances the antifibrotic efficacy of pirfenidone through complementary molecular mechanisms. This data supports the initiation of prospective clinical studies aimed at repurposing PPIs for the treatment of IPF and other fibrotic lung diseases where pirfenidone is prescribed.

PMID:36450789 | DOI:10.1038/s41598-022-24985-x

Targeting of Cdc42 GTPase in regulatory T cells unleashes antitumor T-cell immunity

Fri, 2022-11-25 06:00

J Immunother Cancer. 2022 Nov;10(11):e004806. doi: 10.1136/jitc-2022-004806.

ABSTRACT

BACKGROUND: Cancer immunotherapy has taken center stage in cancer treatment. However, the current immunotherapies only benefit a small proportion of patients with cancer, necessitating better understanding of the mechanisms of tumor immune evasion and improved cancer immunotherapy strategies. Regulatory T (Treg) cells play an important role in maintaining immune tolerance through inhibiting effector T-cell function. In the tumor microenvironment, Treg cells are used by tumor cells to counteract effector T cell-mediated tumor suppression. Targeting Treg cells may thus unleash the antitumor activity of effector T cells. While systemic depletion of Treg cells can cause excessive effector T-cell responses and subsequent autoimmune diseases, controlled targeting of Treg cells may benefit patients with cancer.

METHODS: Treg cells from Treg cell-specific heterozygous Cdc42 knockout mice, C57BL/6 mice treated with a Cdc42 inhibitor CASIN, and control mice were examined for their homeostasis and stability by flow cytometry. The autoimmune responses in Treg cell-specific heterozygous Cdc42 knockout mice, CASIN-treated C57BL/6 mice, and control mice were assessed by H&E staining and ELISA. Antitumor T-cell immunity in Treg cell-specific heterozygous Cdc42 knockout mice, CASIN-treated C57BL/6 mice, humanized NSGS mice, and control mice was assessed by challenging the mice with MC38 mouse colon cancer cells, KPC mouse pancreatic cancer cells, or HCT116 human colon cancer cells.

RESULTS: Treg cell-specific heterozygous deletion or pharmacological targeting of Cdc42 with CASIN does not affect Treg cell numbers but induces Treg cell instability, leading to antitumor T-cell immunity without detectable autoimmune reactions. Cdc42 targeting causes an additive effect on immune checkpoint inhibitor anti-programmed cell death protein-1 antibody-induced T-cell response against mouse and human tumors. Mechanistically, Cdc42 targeting induces Treg cell instability and unleashes antitumor T-cell immunity through carbonic anhydrase I-mediated pH changes.

CONCLUSIONS: Rational targeting of Cdc42 in Treg cells holds therapeutic promises in cancer immunotherapy.

PMID:36427906 | DOI:10.1136/jitc-2022-004806

Personalized medicine approaches in cystic fibrosis related pancreatitis

Fri, 2022-11-18 06:00

Am J Transl Res. 2022 Oct 15;14(10):7612-7620. eCollection 2022.

ABSTRACT

We report a rare case of a patient with cystic fibrosis suffering from debilitating abdominal pain due to chronic pancreatitis. This 13-year-old patient was evaluated for surgical intervention to relieve pain from chronic pancreatitis and to improve quality of life. The patient carried two mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene; the most common ΔF508 variant and a second variant, p.Glu1044Gly, which has not been previously described. The patient's condition did not improve despite medical management and multiple endoscopic interventions, and therefore total pancreatectomy with islet autotransplantation and a near-total duodenectomy was offered for definitive management. Patient-derived duodenal crypts were isolated and cultured from the resected duodenum, and duodenal organoids were generated to test CFTR function. Our studies demonstrate that this novel mutation (ΔF508/p.Glu1044Gly) caused severely impaired CFTR function in vitro. The Food and Drug Administration (FDA)-approved drug ivacaftor, a CFTR potentiator, was identified to robustly improve CFTR function in the context of this novel mutation. Herein, we describe a personalized medicine approach consisting of performing drug testing on individual patient derived organoids that has potential to guide management of patients with novel CFTR genetic mutations. Identified effective medical therapeutics using this approach may avoid irreversible surgical treatments such as total pancreatectomy with islet autotransplantation in the future.

PMID:36398272 | PMC:PMC9641468

<em>gene2gauss</em>: A multi-view gaussian gene embedding learner for analyzing transcriptomic networks

Wed, 2022-07-20 06:00

AMIA Annu Symp Proc. 2022 May 23;2022:206-215. eCollection 2022.

ABSTRACT

Analyzing gene co-expression networks can help in the discovery of biological processes and regulatory mechanisms underlying normal or perturbed states. Unlike standard differential analysis, network-based approaches consider the interactions between the genes involved leading to biologically relevant results. Applying such network-based methods to jointly analyze multiple transcriptomic networks representing independent disease cohorts or studies could lead to the identification of more robust gene modules or gene regulatory networks. We present gene2gauss, a novel feature learning framework that is capable of embedding genes as multivariate gaussian distributions by taking into account their long-range interaction neighborhoods across multiple transcriptomic studies. Using multiple gene co-expression networks from idiopathic pulmonary fibrosis, we demonstrate that these multi-dimensional gaussian features are suitable for identifying regulons of known transcription factors (TF). Using standard TF-target libraries, we demonstrate that the features from our method are highly relevant in comparison with other feature learning approaches on transcriptomic data.

PMID:35854722 | PMC:PMC9285176

Heterogeneous Distribution of Genetic Mutations in Myosin Binding Protein-C Paralogs

Thu, 2022-07-14 06:00

Front Genet. 2022 Jun 27;13:896117. doi: 10.3389/fgene.2022.896117. eCollection 2022.

ABSTRACT

Myosin binding protein-C (MyBP-C) is a sarcomeric protein which regulates the force of contraction in striated muscles. Mutations in the MYBPC family of genes, including slow skeletal (MYBPC1), fast skeletal (MYBPC2) and cardiac (MYBPC3), can result in cardiac and skeletal myopathies. Nonetheless, their evolutionary pattern, pathogenicity and impact on MyBP-C protein structure remain to be elucidated. Therefore, the present study aimed to systematically assess the evolutionarily conserved and epigenetic patterns of MYBPC family mutations. Leveraging a machine learning (ML) approach, the Genome Aggregation Database (gnomAD) provided variants in MYBPC1, MYBPC2, and MYBPC3 genes. This was followed by an analysis with Ensembl's variant effect predictor (VEP), resulting in the identification of 8,618, 3,871, and 3,071 variants in MYBPC1, MYBPC2, and MYBPC3, respectively. Missense variants comprised 61%-66% of total variants in which the third nucleotide positions in the codons were highly altered. Arginine was the most mutated amino acid, important because most disease-causing mutations in MyBP-C proteins are arginine in origin. Domains C5 and C6 of MyBP-C were found to be hotspots for most mutations in the MyBP-C family of proteins. A high percentage of truncated mutations in cMyBP-C cause cardiomyopathies. Arginine and glutamate were the top hits in fMyBP-C and cMyBP-C, respectively, and tryptophan and tyrosine were the most common among the three paralogs changing to premature stop codons and causing protein truncations at the carboxyl terminus. A heterogeneous epigenetic pattern was identified among the three MYBP-C paralogs. Overall, it was shown that databases using computational approaches can facilitate diagnosis and drug discovery to treat muscle disorders caused by MYBPC mutations.

PMID:35832193 | PMC:PMC9272480 | DOI:10.3389/fgene.2022.896117

Pages